Multiple Use of Space and Railway Infrastructure

RAIL ESTATE

MULTIPLE USE OF SPACE AND RAILWAY INFRASTRUCTURE

Sebastiaan de Wilde

Rail Estate Multiple Use of Space and Railway Infrastructure

Sebastiaan de Wilde

Rail Estate Multiple Use of Space and Railway Infrastructure

Proefschrift

ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof.dr.ir. J.T. Fokkema, voorzitter van het College voor Promoties, in het openbaar te verdedigen op dinsdag 12 december 2006 om 15.00 uur

door Theodoor Sebastiaan DE WILDE

civiel ingenieur en doctorandus in de bedrijfskunde geboren te Amsterdam Dit proefschrift is goedgekeurd door de promotoren: Prof.dipl.-ing. J.N.J.A. Vambersky Prof.dr. E.F. Nozeman

Samenstelling promotiecommissie: Rector Magnificus, voorzitter Prof.dipl.-ing. J.N.J.A. Vambersky, Technische Universiteit Delft, promotor Prof.dr. E.F. Nozeman, Rijksuniversiteit Groningen, promotor Prof.dr. D.B. Needham, Radboud Universiteit Nijmegen Prof.ir. A.C.W.M. Vrouwenvelder, Technische Universiteit Delft Prof.ir. H. de Jonge, Technische Universiteit Delft Prof.ir. H.H. Snijder, Technische Universiteit Eindhoven ir. L.I. Vákár, Movares, Utrecht

Publisher: Movares Nederland B.V. Postbus 2855, 3500 GW Utrecht [email protected] / www.movares.nl

ISBN 10: 90-77221-06-9 ISBN 13: 978-90-77221-06-9

Text editing: S.W. Rawcliffe Graphic design: S.P.M. Reinaerdts, Movares Nederland B.V. Print: Drukkerij Mercurius, Wormerveer

All rights reserved. No part of this publication may be used and/or reproduced in any manner without written permission from the author, except in the context of reviews. For the use of photos and illustrations effort has been made to ask permission from the legal owners as far as possible. We apologise for those cases in which we didn’t succeed. These legal owners are kindly requested to contact the publisher.

Alle rechten voorbehouden. Niets van deze uitgave mag worden vermenigvuldigd en/of openbaar gemaakt op welke wijze dan ook, zonder voorafgaande schriftelijke toestemming van de auteur, behalve in de zin van een recensie. Voor het gebruik van foto’s en illustraties is voor zover als mogelijk toestemming gevraagd aan de rechthebbenden. Voor de gevallen waarin dit niet is gelukt, bieden wij onze excuses aan. Deze personen wordt verzocht contact op te nemen met de uitgever. Introduction

Preface

This book is the physical incarnation of five years’ research. For five years, I have had the opportunity to spend my time studying a subject that has fascinated me more and more as time has passed, in an increasingly broad context: multiple use of space and stations. Profes- sor Jan Vambersky and László Vákár suggested that I extend and deepen research on the topic I had studied for my degree dissertation: property development over the railway sidings at Den Haag Centraal. Until then I had never intended to do a doctorate, but I decided to take up the challenge.

The reasons for doing so are closely related to the context. I was given the chance to carry out the research at Movares, the engineering consultancy where I had done my degree project. Working alongside professionals who were dealing with the design of railway infrastructure and stations on a daily basis, I had the opportunity to participate in real-life projects – such as the Multi-storey Dock Model (Stapeldok in Dutch) for the Zuidas in Amsterdam – in parallel with my studies. For the entire duration of the research, I enjoyed the dual role of researcher and consultant, and was free to organise my time as I saw fit. The best of both worlds!

My research on over-track property development started with technical and financial feasibility. Over time, my field of activity – both in research and otherwise – has expanded to encompass property development in the vicinity of the track in general, and I have been devoting increasing attention to the urban architecture, safety, planning and process aspects of this field. Redevelopment projects that involve developing several functions in combination at high levels of density are a growing phenomenon. The impact of urban sprawl on quality of life, mobility and the environment demand new approaches that address these issues while at the same time satisfying the quantitative and qualitative demands for space that stem from our affluence. It is therefore my hope that this research will contribute to the very necessary development of stations and their surroundings as a response to this challenge. Building over the tracks is just one aspect of that subject.

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This thesis would never have seen the light of day without the many people who motivated, informed, inspired and supervised me. A preface is supposed to pre-face the text, so they will have to wait until the closing pages of this work for the thanks they deserve. But I will devote a little space on this opening page to thank my supervisors Jan Vambersky and Ed Nozeman for their willingness to take on that role and for the motivation they have provided through their expertise. László Vákár deserves special thanks, both for giving me the opportunity to conduct my doctoral research entirely within Movares and for encouraging me to keep going and to believe that the project would be a success.

Amsterdam, November 2006

Sebastiaan de Wilde

6 Introduction

Contents

Preface 5

Chapter 1 Introduction 11

1.1 International context 11 1.2 The Dutch context 12 1.3 Challenges of building over and near infrastructure 14 1.4 Current state of research in this field 18 1.5 Research focus and ambition 20 1.6 Research methodology 22 1.7 Reading guide 25

Chapter 2 Multiple and intensive use of space 27

2.1 The history of urban development 27 2.2 The use of space per individual 29 2.3 Optimising the use of space 30 2.4 Multiple use of space 32 2.5 Intensive use of space 36 2.6 Combined strategies 40 2.7 Benefits of multiple and intensive use of space 40 2.8 Conclusion 42

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Chapter 3 Railway stations and railway areas 43

3.1 A renaissance of public transport? 43 3.2 Types of railway station 47 3.3 Functional arrangements of stations 48 3.4 Vertical position of station tracks 52 3.5 Typology of railway stations 54 3.6 Different types of land near railway infrastructure 54 3.7 Urban density: intensive use of space 56 3.8 Mixing functions: multiple use of space 56 3.9 Conclusion 57

Chapter 4 Reference projects 59

4.1 Projects outside Europe 59 4.2 Projects in Western Europe 63 4.3 Selecting the reference projects 66 4.4 Research subjects 68 4.5 London: Broadgate 69 4.6 London: King’s Cross Railway Lands 72 4.7 Paris: Seine Rive Gauche 74 4.8 Paris: Gare Montparnasse 78 4.9 Berlin: Lehrter Bahnhof 80 4.10 Amsterdam: Zuidas 83 4.11 Facts on multiple and intensive use of space 87 4.12 Similarities between the reference projects 89 4.13 Differences between the reference projects 91 4.14 Specific aspects in the Netherlands 93 4.15 Conclusion 95

Chapter 5 Quality and flexibility 97

5.1 A new form of underground construction? 97 5.2 Spatial quality 98 5.3 Transport quality 99 5.4 Urban quality 105 5.5 Aspects of flexibility 111 5.6 Transport flexibility 111 5.7 Urban flexibility 115 5.8 Balancing quality and flexibility 117 5.9 Conclusion 119

8 Contents

Chapter 6 Technical aspects 121

6.1 Railway noise 121 6.2 Railway vibration 127 6.3 Electromagnetic compatibility 131 6.4 Other technical aspects 135 6.5 Conclusion 136

Chapter 7 Physical safety 137

7.1 Physical and social safety in spatial design 137 7.2 Approaches to physical safety 141 7.3 Rules and regulations 143 7.4 Elements of risk analyses 146 7.5 Recent developments in physical safety 151 7.6 HR-3D physical safety concept 153 7.7 Reference projects 159 7.8 Conclusion 163

Chapter 8 Structural design 165

8.1 Railway grids 165 8.2 Building grids 168 8.3 Structural design principles 172 8.4 General consequences of the structural design principles 175 8.5 Basic structural design 181 8.6 Cost comparison 188 8.7 Conclusion 190

Chapter 9 Financial appraisal 193

9.1 Investment for a standard reference office building 193 9.2 Building based on air rights 196 9.3 Extra investment costs for over-track construction 199 9.4 A practical example of determining building investments 200 9.5 Financial risks 202 9.6 Benefits of building over railway tracks 204 9.7 Feasibility of building over railway infrastructure 210 9.8 Conclusion 211

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Chapter 10 Conclusions and recommendations 213

10.1 Main findings and conclusions 213 10.2 Contribution to the field of work 219 10.3 Recommendations 220

References 223

Appendix A Structural calculations 233

A.1 Configuration of the calculation model 233 A.2 Costs of primary bearing structures 237

Appendix B Cost analyses 243

B.1 Extra construction costs 243 B.2 Extra additional costs 250 B.3 Overview of total investment cost 251

Appendix C Interviews 253

C.1 Interviews on reference projects 253 C.2 Interviews for the financial appraisal 254

Summary 255

Samenvatting 261

About the author 267

Acknowledgements 269

10 Introduction

Chapter 1 Introduction

Inner-city building space is becoming scarce. At the same time, there is a heightened awareness that we must preserve the remaining rural areas. Together, these factors are forcing planners to optimise the use of volume in both new and existing buildings. It is possible to optimise the use of space by multiple use of space (meervoudig ruimtegebruik in Dutch) and intensive use of space (intensief ruimtegebruik). Multiple use focuses on combining different functions, intensive use on densification. Space will become even scarcer in the near future, as demands for space per individual are still growing, both quantitatively and qualitatively. Redevelopment or ‘brownfield’ projects can help, because they add new floor space to the city without taking away green areas. Station areas are favourable locations for such projects as they are easily accessible. This thesis will cover a specific area of station redevelopment: the technical and financial aspects of multiple use of space over and near railway infrastructure.

This introduction will first discuss the national and international context of station redevelopment. That is followed by an overview of the challenges inherent in building over and near railway infrastructure and a survey of recent research in the field. The focus and ambition of the present study will be explained, as will the research methodology. The chapter concludes with a guide for the reader.

1.1 International context

The European Union is currently developing a Trans European Transport Network for road, rail, seaports and airports [European Commission, 2005]. At a local level, stations and their surrounding areas are being redeveloped. These initiatives are driven by a complex set of factors, among which are the promotion of sustainable transport and land use [Bertolini & Spit, 1998]. Especially at the nodes of the high-speed rail network (HST), large, complex projects are emerging, in which the station is embedded in high-density urban development

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and redevelopment. London and Paris can boast impressive, large-scale examples and many other projects have been completed, are under construction or are at the planning stage. The HST network involves building new stations and modifying existing ones. Where stations are modified, the aim is both to upgrade them to a quality level in keeping with that of the HST system and to enhance the spatial quality of their surroundings. As travel time is one of the most important factors for passengers, existing inner city stations are well placed, because they link directly into the local public transport system.

In addition to large-scale development and redevelopment of railway areas in cities, there is a general interest in urban revitalisation projects. Boosting the vitality of the city and stimulating sustainable economic development are important objectives [Spaans, 2000]. Urban densification can support the vitalisation and economic development of the city, while new property is gained without the loss of scarce green areas.

Large potential development sites within city centres are often found near infrastructure. These sites are generally underused, either because they are occupied by low density industrial complexes or because stringent environmental regulations are preventing development. Many stations were built at the boundaries of cities between 1850 and 1900. Today these stations have a pivotal position in the urban fabric, as they occupy large, valuable surfaces with tracks and railway-related buildings. In addition, they are usually close to the cultural amenities of the city.

1.2 The Dutch context

In its Vijfde Nota (Fifth National Policy Document on Physical Planning), the Dutch Ministry of Housing, Spatial Planning and the Environment specified that new space for offices, housing and retail had to be found within the ‘red contours’, the existing urban boundaries [VROM, 2000]. The follow up to that document, the Nota Ruimte (National Spatial Strategy), made this policy less rigid, but still required that 40% of all new urban development be within city boundaries [VROM et al., 2004]. Organising the urban planning system in this manner safe- guards the green areas around the cities. As a result, the available space within cities must be used more carefully and efficiently to enable the development of additional floor area.

In addition to the demand for more space, there is a demand for mobility. Over the last 30 years, the car has absorbed the entire increase in mobility. The consequences of car use, with its occupation of space and air pollution, make such alternatives as public transport desirable – air quality near motorways is currently a matter of considerable public concern. Improving both the quality of public transport and accessibility are also matters of governmental policy. The Nota Mobiliteit (mobility policy document) predicts a 20% increase in passenger traffic and a 40% – 80% increase in freight traffic by 2020 [V&W, 2004].

12 Introduction

The development of the high-speed rail network (in red) as part of the Trans-European Transport Network is giving an impulse to many station redevelopment

projects [European Commission] <

Urban planning < areas from the Nota Ruimte [VROM]

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The Dutch government has specifically designated six station areas for redevelopment in connection with construction of the HST network. These six ‘key projects’ are Amsterdam Zuidas, Rotterdam Centraal, Utrecht Centraal, Den Haag Centraal, Breda Station and Arn- hem Station. ‘Masterplans’ have been drawn up, and all six projects are at various stages of development.

However, the reference projects for this study are not limited to these large stations. Plans are underway to develop the areas around several smaller stations. These projects can be roughly divided into two types. The first are those that originate in a desire to modify or expand railway infrastructure. One example is the area around Delft Station, where a tunnel is planned to relieve the city of a railway viaduct, currently both a source of noise and a visual barrier. At the same time, this project is an opportunity for extensive urban redevelopment. The second type are those projects that stem from a need for urban redevelopment. Exam- ples include redevelopment of the area around Zaandam Station: the Inverdan project. Here, an urban revitalisation plan is to give a new impulse to the town’s economy and the station area is an important part of that project. Both examples involve building over railway infrastructure. Delft plans urban development over the future railway tunnels and Zaandam plans to build a library over the existing tracks.

1.3 Challenges of building over and near infrastructure

One feature common to all inner-city station projects is that development of the railway infrastructure and development of property are connected. By railway infrastructure, we mean the track, the structures for the track and the traction power system. By property we mean the buildings, including the station buildings. These two forms of land use do not go together very well. The railway infrastructure limits the options for property development, both because of environmental regulations and because it divides the urban fabric. Property limits the scope for using the infrastructure more intensively and for extending it. As a result, station redevelopment in general and building over the track in particular pose multiple challenges to a range of disciplines. These are discussed below.

1.3.1 A complex field of stakeholders Redevelopment in an inner city area involves a large number of stakeholders, each with their own interests. It takes a complex process to bring these parties together, especially where legal and financial affairs on land ownership and air rights are involved. The stakeholders can be divided into four groups: government parties, railway parties, property parties and the public. This chapter will introduce these parties and their involvement in the process.

Government Government stakeholders can broadly be divided into central and local government. In the Netherlands, development of station areas involves the ministries of VROM (spatial planning) and V&W (transport and public works). VROM is responsible for urban planning and spatial quality, while V&W is responsible for the development of infrastructure. Both ministries invest in station areas, each from its own perspective. The ministry of finance

14 Introduction

is also involved. Local government usually has a significant influence on the development of station areas. It is usually local government that initiates these projects and controls development from concept to completion, starting with the development of a ‘masterplan’ and the setting up of financial arrangements. Government stakeholders can act as a catalyst in the development of station areas by stimulating, facilitating and partly financing the unprofitable parts of these projects. The rationale is that multiple use of space in inner-city areas has public benefits and contributes to the preservation of green belts and rural areas.

Railway Railway stakeholders are divided into the railway management organisation and the train operating companies. The railway management organisation (ProRail in the Netherlands) is responsible for the quality, reliability and availability of the railway network, non-discrimi- natory distribution of network capacity and control of railway traffic [ProRail, 2005]. The railway management organisation is also responsible for the construction of new railway infrastructure and stations and for changes to the existing infrastructure and stations. Train operating companies use the rail network to transport passengers and freight. They benefit from station redevelopment as it increases the number of passengers.

Property Property stakeholders consist of property developers/investors and land owners. Land owners benefit from development plans because redevelopment increases the value of their land, in that the value of a piece of land depends on how much floor space one can develop on it. Both public and private land owners will play a role in station redevelopment projects. Their main priority is high land value, so they benefit directly from initiatives to develop a station area. The property developer’s role is, of course, to develop the land.

The public Individuals will also play a role in a station redevelopment project. On the one hand, there are the railway passengers; they too are stakeholders. Associations of transport users can influence station redevelopment plans. Local residents also exercise influence, as station redevelopment affects a large urban area and residents will want to have their say in the results.

Not surprisingly, projects involving such a wide range of stakeholders, with parallel and conflicting interests, are long and complex. It is a considerable challenge to deal with all these interests and combine them into an overall development plan.

1.3.2 Innovative financing strategies Station redevelopment projects are complex and expensive. Redeveloping a station area can easily take 10 to 20 years. The investments made by public and private parties are closely related, and as a result, public-private partnerships are becoming frequent. Bringing public and private investment together for a project with a lifetime of 20 to 30 years is a major challenge and calls for innovative financing strategies.

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The ownership of land in the project area will influence financing strategy. The ‘masterplan’ must take land ownership into account, in order to facilitate the apportioning of profits on the project at a later stage. In the Netherlands, the air rights over the railways are owned by Nederlandse Spoorwegen (Dutch railways).

Building over railway infrastructure often requires pre-investment, such as the laying of foundations for a future over-track structure. The intention of such pre-investments is to facilitate building over railway infrastructure at a later date and to ensure that this future construction work causes less disruption to railway operations. However, if the over-track structure is not added until many years later, the interest on the pre-investment will mount up. Handling pre- investments is hence an important aspect of financing strategy.

Recouping the extra costs of building over railways requires a combination of high rental income per square metre and a large amount of floor area. A high rental income per square metre alone is not enough, as it is price and volume together that yield the total revenue. The feasibility of marketing a large developed floor area should also be taken into account, as this depends on fluctuations in the property market and on other property development in the region.

1.3.3 Design and construction challenges Building over and near railway infrastructure is difficult. Railway infrastructure is a complex system and train services must be maintained during construction. Building over railways is hence a challenge for the design of the building and for the construction process. Obviously, the two are related. Ways need to be found of assembling the structure rapidly on site and of working within a restricted site area. The inner-city environment may restrict the size of the building elements that can be transported to the site. Building over railway infrastructure is also a challenge as far as logistics is concerned. On the design side, special measures are required to deal with the large over-track spans and with building physics issues. These include noise, vibration, electromagnetic compatibility, air quality and the ingress of daylight to the railway platforms. Buildings have an economic life cycle of less than 50 years, whereas railway infrastructure is designed for over 100. Stacking the railway and property functions will limit the options for modifying either the railway system or the buildings above it.

1.3.4 Safety issues There are particular safety problems related to building over and near railway infrastructure. Firstly, there are the safety aspects of construction and operation. During construction, it is important to select appropriate techniques and to give due consideration to the size of the structural elements, as the consequences of large (multi-tonne) components falling onto the track could be disastrous. During operations, fire safety is a particular concern, and extra precautions must be taken to protect the structure against the consequences of a collision between trains. When multiple use of land results in a railway tunnel underneath the new buildings, the specific rules and regulations applicable to tunnels should be applied, such as those relating to escape routes.

16 Introduction <

Transport of Secondly, one must consider the transport of hazardous goods on the line where multiple hazardous goods use of space is planned. In the Netherlands, for instance, the transport of chlorine and LPG through Eindhoven through urban areas is very common. This form of transport is always a safety risk in densely populated inner-city areas, and it becomes even more of a problem when new urban development is carried out. Specific safety measures are needed when new property is planned over lines that carry hazardous goods. Extra measures are needed to minimise the risk of an incident and to control any that do occur. The number of people killed or injured in any such incident must be minimised.

A third aspect of safety is the growing risk of terrorist attack. Projects involving intensive use of space are targets for terrorism, because a large number of people are concentrated into a small area. Potential threats will therefore influence the design of these projects, as it is possible to prevent certain effects by taking them into account at an early design stage.

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1.4 Current state of research in this field

This section discusses recent research on subjects related to the present study, to place the study in the context of other topics studied recently. Subjects are divided into the station area development process, station area design and the concept of multiple use of space in general.

1.4.1 The station area development process Bertolini & Spit [1998] studied the process of station area redevelopment in five European countries. Two striking observations from their research are that a lot of information is available but no one has the whole picture, and that the process takes up so much time that important project information gets out of date, changes or simply disappears. As a result, people learn relatively little from others participating in the same process and they know very little about station redevelopment projects elsewhere. These observations emphasise the importance of recording the lessons learned in a comprehensive manner. Bertolini & Spit did so for the planning process of the projects they studied.

Berg and Pol [1998] studied the effects of the HST on urban development. Their research was also process related and focused on the planning perspective. They looked at the question: ‘How can the high-speed train make an optimum contribution to the long-term development of well being in urban regions?’ They researched the effects on accessibility, economic potential, spatial quality, distribution of functions, distribution of social effects and organising capacity. In his PhD thesis, Pol also researched economic effects, development strategies and operational issues related to European HST stations [Pol, 2002]. Research has also been undertaken on development strategies for creating synergy at station locations. Peek [2001] studied the added value that can be created for both the railway infrastructure and the city when the station area is developed.

A new field of research has emerged, on Transport Development Areas (TDA) or Transit Oriented Development (TOD). A Transport Development Area is an integrated land use/ transport planning approach, centred on urban public transport interchanges or nodal points well served by public transport, in which a more specific relationship between development density and public transport service level is instituted [Hine, 2000]. The term ‘Trans- port Development Area’ is associated with English projects. Transit Oriented Development is an American planning principle with a similar definition. TOD has experienced enormous growth in America, where it is a common approach, involving the use of mass transit and high density urban development to combat transport congestion and urban sprawl [Dittmar & Ohland, 2004]. Literature on TDAs and TODs focuses on planning mechanisms and examples of real-life projects.

1.4.2 Design of stations and surrounding areas Where architects and urban designers have studied the design of stations and surrounding areas, their work is mostly based on practical knowledge. Literature is available on the design philosophies of different architects. Von Gerkan [1996 & 1997] describes his architectural design philosophy for airports and stations in Renaissance der Bahnhöfe

18 Introduction

(Renaissance of Railway Stations). He specifically describes the changing position of the railways in our developing cities and gives recent examples of the integration of new stations into existing inner-city areas. Agence des Gares / Arep [1998], Foster [2001] and Kool- haas [1993] describe similar visions on the position of railway infrastructure in cities, but also include only the social and architectural perspective. Ross [2000] takes a more general look at of station development.

Structural engineers Vákár & Snijder [2001] analysed the technical aspects of station design in densely populated areas. They discuss quality and flexibility in relation to the structural design and construction of stations and their surrounding areas, partly on the basis of real-life examples. In 2000, DEGW carried out a broad study on superstructure projects in station areas [DEGW, 2000a & 2000b]. This study was commissioned by the Dutch ministry of housing and NS Vastgoed, the property department of the Dutch railways. It mainly addresses technical issues, and deals with some of the Dutch ‘key projects’ mentioned earlier.

Most other research on building above infrastructure has concentrated on specific sub-areas of the topic.

1.4.3 Multiple use of space Inner-city redevelopment projects are often a combination of different functions. Mixed use development has become a broad field of study, as it has been viewed as a positive contribution to planning policy [Coupland, 1997]. Mixed use development, or multiple use of space, has mostly been studied from a planning and an architectural point of view. The structural design and construction methods involved in such projects have attracted little attention so far.

The Habiforum foundation is conducting general research on multiple use of space in the Netherlands [Habiforum, 2003]. Priemus et al. [2000] defined the term ‘multiple use of space’ and researched its driving forces and the obstacles it encounters for Habiforum. That research focuses on social changes that promote multiple use of space and the process aspects that impede its application. In addition to more general research on the background and practice of multiple use of space, specific areas are researched more in depth. The table below gives a short overview of work done by Habiforum and others.

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Subject Research Economics Researchers at the Free University of Amsterdam are studying multiple use of space from a planning/economic point of view. Rodenburg [2005] studied infrastructure and synergy, and measured the benefits of multiple use of space by means of stated preference studies. Vreeker [2002] studied the assessment of spatial quality and multifunctional land use. Safety Safety is an important aspect of multiple use of space. Two major disasters in the Netherlands (in Volendam and Enschede), combined with a number of tunnel accidents in Europe, have heightened public interest in physical safety. In Enschede, an explosion in a fireworks warehouse swept away a complete neighbourhood and in Volendam several teenagers died when a café caught fire. Suddle has researched the physical safety of projects that involve multiple use of space by building over infrastructure and existing buildings [Suddle, 2004]. Legal Breedveld has studied the legal and fiscal aspects of property development over infrastructure [Breedveld, 2002]. Stoter and Ploeger have looked at a three-dimensional property register for situations involving multiple use of space [Stoter & Ploeger, 2003]. Urban design In his PhD thesis, Van der Hoeven [2001] explored the potential advantages of underground construction for integrating main roads and motorways into their environment. He analysed the possibility of covering over the Amsterdam and Rotterdam ring roads. The research focuses on projects involving road infrastructure and is a combination of urban design and civil engineering. Another reason for studying multiple use of space is that it can save space. Sustainability Building within existing city boundaries preserves rural areas and can have positive side effects on the environment. Dobbelsteen [2004] studied the impact of space use on sustainability, distinguishing three dimensions of sustainability: technology, space and life span. His results are used in this thesis.

1.5 Research focus and ambition

This research is intended to contribute to the field of property development over and near railway infrastructure. The focus is on the technical and financial aspects. Little knowledge is available in these two areas, beyond figures from individual projects. The work of Bertolini and Spit [Bertolini & Spit, 1998] has already shown that such information as is available is fragmented, that there is no comprehensive overview and that those involved in such projects learn little from each other. Furthermore, there is no single piece of research that combines the technical and financial aspects of these projects. Comprehensive and systematic knowledge of the technical and financial aspects could act as a lever, making more such projects possible. The parties involved can be brought together if there is a deeper understanding of the investment required.

20 Introduction

The research includes analysis of projects outside the Netherlands, but owing to the many differences between the Dutch situation and that obtaining elsewhere, specific solutions and cost analyses will focus on Dutch practice. It may well be possible, however, to apply the knowledge acquired to situations in other countries.

Problem statement: There is a growing need to conduct projects involving multiple use of space over and near railway infrastructure, but little is known about the technical and financial aspects of such projects, and such knowledge as exists is fragmented.

Integrating the available knowledge and developing new knowledge form the main objectives of this research. The two related problems are that what knowledge exists is fragmented and inaccessible to the stakeholders in property development over railway infrastructure, and that there are many gaps within this fragmented knowledge.

Main research question: What are the technical and financial constraints on multiple use of space over and near railway infrastructure?

The following specific questions can be derived from this main question: 1 What is multiple use of space? What types of multiple use of space are conceivable and what forms do they take in practice? This part of the study also involves looking at intensive use of space and combinations of intensive and multiple use. 2 What is railway infrastructure? Typologies of railway infrastructure. Railway infrastructure – tracks and stations – forms the area in which property over railways is constructed. This infrastructure limits the options for structural design and for construction processes. 3 What can be learnt from reference projects outside the Netherlands? Projects in other countries can tell us much about technical and financial conditions. Suit- able reference projects abroad must be identified and researched in depth, to gather up-to-date information on recent practice. 4 What are the technical boundaries of building over railways? These are a combination of ‘hard’ and ‘soft’ boundaries. Soft boundaries consist of the design requirements that must be met in order to ensure the quality and flexibility of projects. What are the quality requirements with regard to the railway infrastructure and its urban surroundings, and how can infrastructure and property be made flexible, so as to meet future requirements? Hard boundaries are formed by such technical aspects as noise, vibration and electromagnetic compatibility. It is necessary to avoid nuisance from these sources, so effective and cost effective measures will be researched and defined. 5 How should we deal with safety? Physical safety requirements are rapidly becoming more stringent. High-density property over and near stations exists in parallel with the transport of hazardous goods through many of these stations. As a result, safety forms an integral part of this research. Safety is also important during construction .

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6 What are the structural options for building over railway infrastructure? Building over railway infrastructure will demand specific over-track structures. Concep- tual solutions for these specific structures will be designed, and their technical feasibility and costs assessed. The structural solutions adopted must be consistent with the results of the research on technical boundaries and safety. 7 What are the costs and benefits of building over railways? We can determine the costs of building over railway infrastructure, partly from the structural solutions adopted. These costs can be compared with those of ‘normal’ property in inner city areas. The benefits of building over railway infrastructure will also be compared with such property. The feasibility of building over railway infrastructure will be determined on the basis of costs, benefits and land values.

The above framework is a broad one. This research focuses on the structural design principles of over-track structures, together with the costs and benefits of these buildings. It is hoped that this study will contribute to the multiple use of space over railway infrastructure. By combining technical and financial aspects, the research will enhance knowledge in the field of multiple use of space. The work also forms an addition to the existing body of knowledge, which hitherto has concentrated on the planning process. The research ambition is defined as follows:

Research ambition: To integrate available knowledge on the theory and practice of building over railway infrastructure and to develop new knowledge in this field, in order to find general structural solutions, calculate the cost of such solutions and determine the financial feasibility of this type of project.

1.6 Research methodology

The research is multi-disciplinary and the available knowledge is highly fragmented. The methodology has been adjusted to the information available and the knowledge needed to achieve the research aim of identifying structural solutions, calculating their costs and determining the feasibility of projects. The research questions listed above determined the structure of the thesis, which is presented below. The research can be divided into four parts:

First part: Two introductory chapters. The first of the two discusses the background of multiple and intensive use of space and the definitions of these terms. The second addresses railway infrastructure.

Second part: A study of reference projects outside the Netherlands that involve the multiple use of space over railway infrastructure, summarising the state of the art in this area.

Third part: Technical aspects and structural design. The technical requirements of multiple use over railway infrastructure are established, and conceptual structural solutions developed based on those requirements.

22 Introduction

Fourth part: A financial appraisal of multiple use of space over railway infrastructure.

Introduction (Chapter 1) < Multiple and intensive use of space (Chapter 2) Structure Part 1 Railway stations and railway areas (Chapter 3) of the thesis

Part 2 Reference projects (Chapter 4)

Quality and flexibility Technical aspects Physical safety (Chapter 5) (Chapter 6) (Chapter 7) Financial analysis Part 3 Part 4 (Chapter 9)

Structural design (Chapter 8)

Conclusions and recommendations (Chapter 10)

The methodology distinguishes between three research levels: gathering available knowledge, developing new knowledge and integrating knowledge. Up-to-date knowledge on theory and practice was gathered for all subjects by means of desk research, interviews, project visits or such other means as were necessary. For some parts, the knowledge available was sufficient to fulfil the research ambition, while in other areas it was necessary to develop new knowledge. Finally, research on the individual subjects was integrated into conceptual structural solutions and the financial appraisal.

1.6.1 Part 1: Introductory chapters There are two introductory chapters to this research. These set the wider context of the research and the social developments that drive the development and redevelopment of station areas.

The first introductory chapter (Chapter 2) discusses the concepts of multiple and intensive use of space and how they are integrated into inner-city areas. The benefits and challenges are analysed and various concepts are explained by reference to actual projects. Desk and field research was conducted on the multiple and intensive use of space. The desk research addressed definitions of the concepts and theories of multiple and intensive use of space, while field research was undertaken to draw up a list of example projects.

The second introductory chapter (Chapter 3) discusses railway infrastructure. This chapter investigates the utilisation of Dutch railway infrastructure on the basis of statistics and proposes a typology of stations. The manner in which integration of the station into the urban fabric determines the options for further urban development is analysed. The chapter also studies railway land and the possibilities it offers for the multiple and intensive use of space. Like Chapter 2, this chapter is the result of a combination of desk and field research.

23 Rail Estate

1.6.2 Part 2: Reference projects Building over railway infrastructure is often part of a larger urban redevelopment project. This second part of the research makes an inventory of current reference projects in West- ern Europe, before analysing and comparing a selection of these projects in depth. Analysis covers the history of such projects, how they are integrated into their urban environments, their use of land, their combination of urban functions and their structural design. The results highlight similarities and differences between projects. The chapter also draws specific conclusions for the Dutch context.

This part of the research is based on desk research, field research and interviews. The desk research established the list of reference projects involving property over tracks and gathered detailed information on those projects. As literature on reference projects is scarce, field research was conducted on those projects that were analysed in depth. In addition, interviews were conducted with people involved in the projects.

1.6.3 Part 3: Technical aspects and structural design The research on technical aspects and structural design is divided into four chapters. The first chapter (Chapter 5) deals with the ‘soft’ technical boundaries – quality and flexibility – while the second chapter (Chapter 6) discusses the ‘hard’ technical boundaries – noise, vibration and electromagnetic compatibility. The third chapter (Chapter 7) covers physical safety. The last chapter of this part of the research (Chapter 8) proposes conceptual structural solutions on the basis of the three previous chapters.

Projects involving multiple use of space can substantially change the station area. Chapter 5 discusses the impact of these changes on quality and flexibility. Quality and flexibility can be seen as ‘soft’ technical boundaries. Chapter 5 is mainly the result of field research on projects that involve building over the track. There was little literature that dealt specifically with construction over railway infrastructure. The available knowledge on these subjects in a broader context has been used to develop a framework for formulating requirements in these areas. However, detailed design suggestions do not form part of this research, as they do not substantially influence the conceptual structural solutions or the financial appraisal.

Chapter 6 discusses technical aspects of building over and near railway infrastructure: noise, vibration and electromagnetic compatibility. The chapter also deals briefly with certain other technical issues. The aspects discussed can be seen as ‘hard’ technical boundaries. This part of the research is mainly based on desk research. Sources included degree dis- sertations on noise and vibration nuisance. For these subjects, the knowledge available was sufficient for the purposes of the present research.

Physical safety is a specific and very important aspect of the multiple use of space. Espe- cially in the Netherlands, where transport of hazardous goods by train through densely populated areas is permitted, knowledge of the impact of accidents and how to prevent them is indispensable. Chapter 7 focuses on the risks inherent to multiple use of space above railway infrastructure and on the measures that are required. The chapter also looks at the appli- cability of available rules and regulations, as there is little experience with their application.

24 Introduction

This chapter is based on desk research. As available knowledge was not sufficient to fulfil the research ambition, new knowledge was developed by creating a new physical safety concept. That concept addresses measures and risk calculations related to building over and near railway infrastructure.

Chapter 8 develops conceptual structural solutions, partly by integrating the design requirements formulated in the previous chapters. The chapter involves developing conceptual designs for various types of over-track structure. By varying the parameters of a model, it was possible to estimate how structural design choices affect the extra costs of a primary bearing structure over railway infrastructure.

1.6.4 Part 4: Financial appraisal The last part of the research is a financial appraisal of building over railway infrastructure. Chapter 9 estimates the investment required for an over-track office building, including the extra costs for the primary bearing structure. This cost estimate was developed in collaboration with cost engineers who deal with such projects in practice. The benefits were determined by desk research and by interviews with Dutch property developers and investors. The value of air rights above railway infrastructure was determined by establishing the difference between the extra cost of building over railway infrastructure and the value of the land beside the infrastructure that could have been used instead. Any extra benefits associated with building over railway infrastructure may add further value to air rights.

1.7 Reading guide

This research is aimed at all parties involved in either multiple use of space or railway infrastructure. All need to work together in order to create and use the railway system and the property above it, on what is often a small area of land. Integrated research into the technical and financial aspects of developing property over and near the railway brings new insights that can facilitate the complex processes involved.

As the development of such property is a multidisciplinary activity, not all parts of this thesis will be equally relevant to all readers.

• Readers with a general interest in the development of station areas, multiple and intensive use of space, and reference projects that involve building over railway infrastructure: Chapters 2 to 4. • Readers with an interest in the requirements of such projects: Chapters 5 to 7 (Chapter 5 being of particular interest to designers and Chapters 6 and 7 more to engineers). • Readers with a specific interest in the structural design of buildings over railway infrastructure: Chapter 8 and Appendix A. • Readers involved in cost engineering, property development and property investment: Chapter 9 and Appendix B.

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26 Introduction

Chapter 2 Multiple and intensive use of space

As indicated in the introduction, there is a need to use inner-city space more efficiently. Two recent approaches to achieving more efficient use of space are multiple use of space (meervoudig ruimtegebruik in Dutch) and intensive use (intensief ruimtegebruik). This chapter will start with some facts and figures on the use of space in cities before moving on to the general principles associated with optimising the use of space. We shall propose definitions for the two terms multiple use of space and intensive use of space and discuss ways of achieving both, in theory and in practice. The chapter concludes with an introduction to the general benefits of the two approaches.

2.1 The history of urban development

We can divide use of urban space into three phases: up to 1850 (the pedestrian era), 1850 – 1950 (the railway era) and 1950 to the present (the car era). Until the nineteenth century, walls defined the city boundary, enabling the city to defend itself in times of war. Urban growth occurred in two ways: more intensive use of space within the walls, and construction of new walls further from the centre. In part, the new walls enclosed new buildings constructed outside the old ones. Nevertheless, cities remained small and everything was within walking distance.

The second phase started in the nineteenth century. The number of city-dwellers had grown rapidly with the industrial revolution, which brought the steam engine and the railway. The growing number of inhabitants and daily visitors led to congestion problems in the cities and caused land values to rise [Wagenaar, 1998]. At the same time, large-scale construction of railway infrastructure took place. Railway terminals were built at city boundaries, where city walls had lost their function. All major European cities have terminal stations on their outskirts. Examples include St Pancras Station in London and the Gare du Nord in Paris. In the Netherlands, the construction of the railway network ran parallel to the dismantling of city walls [Dijksterhuis, 1984]. From that point, cities grew much faster in terms both of

27 Rail Estate To Gare du Nord

To Gare St Lazare To Gare de l’Est

Development of Paris between 1100 and 1871 [based on Justus Perthes]. Construction To Gare de Lyon To Gare Montparnasse took place within the existing walls To Gare d’Austerlitz and new walls Size of the old city (Ile de la Cité) were built, each City size under Louis VII (1127 - 1180) enclosing a larger City size since Philippe Auguste (1180 - 1223) area than its Boulevard created since Louis XIV City walls build since Louis XVI (after 1781) < predecessor. City walls around 1871 (Boulevard Périphérique at present)

< Development of Paris between about 1860 (red) and 2006 (orange). Motorway infrastructure enabled suburbanisation over a large area.

28 Multiple and intensive use of space

population and of square metres occupied. Public transport systems were built within cities, both to link the new railway terminals and to improve inner city transport. The Circle Line on the London Underground is one example. Paris had a similar circle line, used primarily for freight [Wagenaar, 1998].

The third phase started after World War II with the growth of transport by car and of the associated motorway infrastructure. Car use grew extremely fast, creating a need for new infrastructure. Cities built orbital motorways to link transport axes, such as the Boulevard Périphérique around Paris and the A10 around Amsterdam. Improved infrastructure and the fact that most commuters were able to buy a car caused cities to grow even faster. Suburbanisation resulted in large-scale, mono-functional urban sprawl.

The development of infrastructure and the possibility of travelling further in the same time have had a huge influence on urban growth. One effect has been suburbanisation. Today, many cities have swallowed up so much of the countryside around them as to make saving what remains an environmental necessity. Such new development strategies as brownfield development are attracting much attention, and new ways of looking at the use of urban space are emerging. Rural areas will function as new, virtual city walls, with the difference that they are intended to protect the surroundings from the city rather than the city from the surroundings.

2.2 The use of space per individual

If the population increases and the amount of land remains fixed, the available space per individual decreases. Research in the countries of the European Union shows differences in population density. The Netherlands is the most densely populated country in Europe. The problem of lack of space, prompting projects involving intensive and multiple use of space, is therefore more acute than in other countries. Lack of space in the Netherlands does not necessarily mean lack of space in cities for housing and offices. The problem is more the lack of space for extensive space-users such as recreation and water. In the future, the only sector whose demands for space will decrease is agriculture. However, this does not mean that more efficient use of space in cities is any the less urgent.

Population density

Population < 500 475 densities in 450 2 400 countries of the 350 338 300 European Union 247 250 231 193 [source: CBS, 200 172 150 112 125 2003] European Union 80 81 97 109 100 Inhabitants per km 55 50 17 22 0

Italy Spain France Finland Sweden Ireland Greece Austria Belgium Portugal Denmark Germany Luxembourg Netherlands United Kingdom Country

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While the Netherlands is the most densely populated country in Europe, its cities are far less densely populated than metropolitan cities in other countries, such as London or Paris. In the Netherlands, pressure on space is a national problem rather than a local one. Because there is no local pressure on space, the value of land in inner cities is relatively low. At the same time, high land value is an important precondition for building complex, high-density urban projects involving multiple and intensive use of space, as such projects are usually expensive. The higher urban densities of Paris and London result in higher land values and, as we will demonstrate in the following chapters, in more large-scale projects involving multiple and intensive use of space.

Population density < Population density of metropolitan 50 000 45 532 2 45 000 cities (Dutch cities 40 000 35 000 in red) [source: 30 000 25 517 23 460 25 000 20 952 www.onstat. 20 000 13 300 amsterdam.nl 15 000 9 615 7 407 10 000 5 511 6 089 Inhabitants per km 2 708 2 869 3 000 3 571 4 419 4 583 (Dutch cities), 5 000 1 210 0 2005/Shanghai Urban Planning Utrecht Chicago and Design Randstad The Hague Rotterdam Amsterdam Hong Kong City of Paris New York CityShanghai City Inner London Los Angeles WashingtonCity DC Greater London Research Institute Hong Kong, Kowloon New York, Manhattan (Shanghai), 2004/ City www.demographia. com (London), 2005/Heijer et 2.3 Optimising the use of space al. (other figures), 2003] Optimising the use of space is becoming a challenge for many cities. There are different approaches, but basic steps include mixing (multi-functionality) and stacking [Dobbelsteen & Wilde, 2004].

Stacking < Strategies for optimising the use One layer More than one layer of space on an urban scale

One function Intensive use of surface by Intensive use of land by increasing occupation rate adding more building layers

More than one function Multiple use of surface by Multiple use of land by stacking

Multifunctionality combining different functions different functions

Starting from one function with one building layer, the first way of optimising the use of space is to increase the occupancy rate. Another option is to stack building layers. Stacked functions occupy less land, making more efficient use of the available space. Another strategy is to combine different functions, which saves space. Using the same parking space for offices

30 Multiple and intensive use of space

and for dwellings is one example. A mixed development consisting of housing and offices also needs less public space. It is possible to combine the two strategies by stacking different functions. The concept of adaptability over time applies to all four of these strategies. It is hence possible to optimise the use of space by means of solutions in four dimensions: length, width, height and time, and by combining functions.

It is possible to develop various concepts for improved space use. Intensification in two dimensions is achieved by increasing the occupancy rate (intensive use of surface), either at urban level or in terms of separate functions. Intensification in three dimensions is possible by stacking building layers (intensive use of land). Functions can be combined in two dimensions (multiple or mixed use of surface) or in three dimensions (multiple use of land). It is possible to achieve a longer useful life span by means of intensive use, or prolonged use over time in the case of a single function, and multiple or sequential use over time in the case of multiple functions. A longer life cycle improves the distribution of costs over time, e.g. for the foundations and the building structure. It is possible to combine these four strategies in an urban area, perhaps by mixing functions (multiple or mixed use of surface), which are also

stacked (intensive use of land). Possible concepts < Increase Intensive use for improved use occupancy of surface of space

Intensive use Mix & stack Stack 3 x of land

Multiple or Mix mixed use of Multiple use surface of land

Intensive or Use longer prolonged use over time

Multiple or Adapt over sequential time use over time

We shall refer to the mixing of functions as multiple use of space and the intensification of space use as intensive use of space. These two concepts will be developed further in the following sections.

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2.4 Multiple use of space

Most of the relevant literature defines multiple use of space as a combination of different functions. Priemus et al. [2000] give the following definition: “More than one function in a given space at a given time.” Harts et al. [1999] define multiple use of space as: “The presence of different functions close to each other or in the same area.” Both definitions treat the combination of different functions as a measure of multiplicity. In its fifth national policy document on spatial planning, the Dutch Ministry of Housing, Spatial Planning and the Envi- ronment does not discuss multiple use of space as a notion but discusses the combination, transformation and intensification of functions [VROM, 2000].

In many cases, multiple use of space seems to function as a collective term for all projects where the use of space is intensified, where different functions are combined in space or time, or where both intensification and mixing are used. So how shall we define multiple use of space? The available definitions are very broad. Coupland indicates that there are many definitions of mixed use, mainly based on the combination of two or more functions, leaving many interpretations and considerable confusion [Coupland, 1997]. For instance, a car park under a supermarket that is used only by the supermarket’s customers does not constitute multiple use of space, as the car park is part of the function. So functions in a project must not only differ, but they must also be independent. But even though functions must differ for the situation to constitute multiple use of space, synergy between the different functions is important if the multiple use of space is to bring any benefit. We can distinguish between three forms of multiple use of space. The following sub-section gives examples from Dutch practice.

Multiple use of space < Different forms Multiple or mixed use of surface of multiple use (Second dimension) of space

Multiple use of land (Third dimension)

Multiple or sequential use of land (Fourth dimension)

32 Multiple and intensive use of space

2.4.1 Second dimension: multiple or mixed use of surface Multiple or mixed use of surface is multiple use of space in the second dimension, i.e. placing functions next to each another. Examples include the Resident in The Hague and the Bijlmer station area in Amsterdam.

The Resident, The Hague

The Resident, < This example of mixed use of surface is located a new mixed use in The Hague, near Den Haag Centraal Sta- project in the tion. The Resident is a new urban development centre of The Hague consisting of offices and flats, located next to one another rather than superimposed. The functions are used independently. It is also an example of intensive use of space, with a large amount of property on a small piece of land. This combination of functions occurs in every city, but the fact that the buildings were developed in one project makes it multiple use of space.

Bijlmer station area, Amsterdam

Mixed use < The Bijlmer redevelopment project started development in in 1996 with completion of the Amsterdam the new Bijlmer Arena, the multi-functional stadium of Ajax station area football club. Offices, residential buildings and a large number of facilities have been built around Amsterdam Bijlmer Station. Recon- struction and enlargement of the railway and metro station is part of this project. Approxi- mately 800 000 m2 of property (mainly offices) has been built on 65 hectares [Gemeente Amsterdam, 1997]. This project constitutes multiple use of space because different functions combine to strengthen each other.

2.4.2 Third dimension: multiple use of land Stacking two or more functions constitutes multiple use of land. Three ways of stacking buildings on top of other functions are presented below: over road infrastructure, over railway infrastructure and over existing buildings.

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Over road infrastructure: New Metropolis, Amsterdam Amsterdam’s new technology museum, < New Metropolis, New Metropolis, has been built on the tunnel a museum over an existing tunnel connecting the city centre with Amsterdam entrance in North. The functions of road infrastructure Amsterdam and museum have been stacked, with the new building using the existing tunnel foundations.

Over railway infrastructure: Traffic Square, Rijswijk Two buildings have been built over Rijswijk Sta- tion: an office block and flats. The first building, Traffic Square, stands on the south end of the tunnel. The other building is located over < Traffic Square, the middle of the tunnel. Currently, there is an office building over a new railway no building over the other end of the tunnel, tunnel in Rijswijk but the foundation structure has already been prepared. The time lag between construction of the tunnel and construction of the buildings overhead was short.

Above an existing building: Nederlands Congres Centrum, The Hague A four star hotel has been constructed on top of the existing Nederlands Congres Cen- < Nederlands trum in The Hague. In other words, a new Congres Centrum: a new hotel function has been erected above an exist- over an existing ing function, creating multiple use of land. congress centre The congress centre remained in use while in The Hague the hotel was under construction [Meijer & Visscher, 2001]. In this instance, the overhead building was constructed a long time after the original building, and the original structure was not designed for an overhead building.

2.4.3 Fourth dimension: multiple and sequential use over time When the use of a certain space changes, we can speak of either multiple or sequential use over time. Using a building for more than one function simultaneously is referred to as multiple use over time, whereas using a building first for one function and then for another is referred to as sequential use over time. Multiple use over time is more difficult to organise, as most spaces are designed for a single use and a single user. Sequential use over time is more common; it occurs whenever a building is redeveloped for a new function.

34 Multiple and intensive use of space

Multiple use over time: Pathé Theater, Amsterdam

Pathé Theater, < The Pathé Theater is located near Amster- a cinema near dam Bijlmer Station. It is primarily a cinema, Bijlmer Station but is sometimes used for congresses and in Amsterdam seminars during the day. This combination of business and leisure use is an example of multiple use over time; two different functions use the same space one after the other within a limited period.

Sequential use over time: warehouse converted into flats, Amsterdam

Warehouse < In many cities, old warehouses have recently converted into been redeveloped into luxurious apartment luxury flats buildings. Examples are found in the harbour in Amsterdam areas of Amsterdam, Rotterdam and London (along the Thames between Canary Wharf and Tower Bridge).

2.4.4 Definitions Following on from the discussion above, these are the definitions of the different types of multiple use of space that will be used in this study:

Multiple use of space: The use of space for more than one function in the second, third or fourth dimension, where the functions are also used separately and independently. Mixed use of surface: The use of space for more than one function horizontally. Multiple use of land: The use of space for more than one function, with the functions stacked vertically. Multiple or sequential use over time: The use of space for a sequence of functions, short term or long term.

It is difficult to define the extent to which multiple use of space occurs in urban development. Whether we define a situation as involving mixed functions depends on the scale we take into account. On a larger scale, there will always be combinations of functions (e.g. if we look at the whole of the centre of Amsterdam). For the purposes of this research, we shall define as ‘multiple use of space’ only those projects that combine functions within a new plan.

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2.5 Intensive use of space

The intensive use of space is more subjective than multiple use. ‘Intensive’ is in the eye of the beholder. Someone from Tokyo will look at Amsterdam as a relatively unintensively used space, whereas Dutch people see the use of space in Amsterdam as intensive. So what is intensive use of space? We could say that a site is being used intensively when it is used more intensively than its direct surroundings or more intensively than it was before redevelopment. We can then compare a given space to its surroundings on the same scale in terms of square metres of development per hectare.

The floor space index (FSI) is an objective measure of the intensity with which space is used [Berghauser Pont et al., 2002]. The FSI is the ratio of the total gross floor area to the total ground area on which it has been constructed. The FSI therefore has a three-dimensional character and is a measure of urban density. We can calculate the FSI of a city as a whole, of urban districts or plans, or of individual sites. The terms floor area ratio (FAR) and plot ratio (PR) are also used [MVRDV, 1998 & Argent St George, 2001]. These are the same as the FSI. An FSI of 2 means that 20 000 m2 of property occupies one hectare of ground surface (10 000 m2). Cities like New York and Tokyo have a much higher density than the Nether- lands. Manhattan has an FSI of 6, for example [MVRDV, 1998]. Tokyo had an area with a designated FSI of 10 as early as 1965 [Bongenaar, 1996]. We can also distinguish different forms of intensive use of space in the second, third and fourth dimensions.

Intensive use of space

Intensive use of surface (Second dimension)

Intensive use of land (Third dimension) < Different forms of intensive use of space Intensive or prolonged use over time (Fourth dimension)

2.5.1 Second dimension: intensive use of surface The use of surface is intensive when a large percentage of the surface of an area is used. Berghauser Pont et al. define a ground space index (GSI) as the ratio of the land that has been built on to the total land surface [Berghauser Pont et al., 2002]. They class the GSI of an urban area as ‘high’ from about 0.3, i.e. when 30% of a site is occupied [Berghauser Pont et al., 2002].

36 Introduction

Intensive use of space in Tokyo, Koshu

Kaido Avenue [Paul Chorus] <

Intensive use of < space in New York, Manhattan

37 Rail Estate

Oostoever, Amsterdam The district of Oostoever is an example of < Oostoever, a high- intensive use of surface. Density here is density housing development in 77 houses per hectare [Coördinatieteam Amsterdam Optimalisering Grondgebruik, 2001]. A relatively high percentage of the land has been used for dwellings. This project is not an example of multiple use of space, because housing is the only function in this area. Koolhaas indicates a Dutch planning standard of about 50 houses per hectare [Koolhaas, 1995]. New suburbs known as VINEX-wijken have a density of only about 30 houses per hectare [Kolpron & Neprom, 2000]. Oostoever therefore counts as intensive use of space.

2.5.2 Third dimension: intensive use of land Land use is intensive when a piece of land contains a large amount of floor area, i.e. it has a high floor space index (FSI). Multi-storey buildings are one way of attaining a high FSI, so intensive use of land has a close relationship with the third dimension. According to Berghauser Pont et al., a ‘high’ FSI for urban areas starts at around 1.0 [Berghauser Pont et al., 2002].

World Trade Center, Rotterdam A high-rise office block has been built above < The WTC in the existing Rotterdam Exchange Building. Rotterdam is stacked on the Modern construction techniques have made existing exchange it possible to add new floor area to an exist- building and con- ing building. Both buildings are part of the structed through it same function, namely the Rotterdam World Trade Center. This is therefore not an example of multiple use of space. It is, however, a good example of intensive use of space, both because the FSI of the site has increased and because the FSI is higher than that of neighbouring sites.

2.5.3 Fourth dimension: intensive or prolonged use over time Both intensive and prolonged use over time increase the total hours that the building is used over its lifespan. Intensive use over time means using the building for more hours per day. Prolonged use means extending the lifespan of the building.

38 <

Before and after Intensive use over time: shopping centres views of the Atrium Offices and dwellings are mostly used at specific times of the day. Offices are occupied building in the between 08.00 and 18.00, with little scope for extending this period. The same is true Zuidas of dwellings – generally, it is not possible to increase the number of hours per day during which a dwelling is used. Other functions can be extended. Shops can remain open later, for instance.

Prolonged use over time: Atrium, Amsterdam The old NMB bank building near Amsterdam Zuid WTC Station was renovated in 1989. The office concept was out of date, but the existing structure could be re-used. The façade, glaz- ing and interior were completely replaced (see photos). The building is now called the Atrium and is one of the most expensive office buildings in the Zuidas (an important business district in Amsterdam).

2.5.4 Definitions For the purposes of this research, we shall define the different types of intensive use of space as follows:

Intensive use of space: More intensive use of a space compared to either its direct surroundings at the same scale or its previous use. Intensive use of surface: Denser or more intensive use of a space at ground level compared to either its direct surroundings at the same level of scale or its previous use. Intensive use of land: More intensive use of a piece of land in square metres per hectare, compared to either its direct surroundings at the same scale or its previous use. Intensive or prolonged use over time: Using a certain space intensively over time, short or long term.

As with multiple use, it is difficult to define the extent to which intensive use of space occurs in urban surroundings. Generally, new development or redevelopment creates a higher density than before. This is even true of greenfield projects. For the purposes of this research, we shall define as ‘intensive use of space’ those projects with a higher density than their direct surroundings on the same scale.

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2.6 Combined strategies

Many solutions involve both intensive and multiple use of land. One example is the stacking of functions that would normally be situated next to each other: the same programme is concentrated into a smaller area and therefore intensified, and at the same time it involves more than one function, making it multiple. However, not all cases of multiple use of space involve intensive use of space and vice-versa. Optimising use of space can be seen as an integrated approach to both concepts. There are different ways of making intensive and multiple use of space at different scales.

Space use Scale < Practical ways of optimalisation City/district Site Building layer optimising use of space in Intensive urban areas

Multiple Second dimension: use of surface

Intensive Third Multiple use of land dimension: Dimension

Intensive

Multiple Fourth use of time dimension:

As shown earlier, we can characterise multiple use of space and intensive use of space in a comparable manner, even though these are different solutions. Whether space is intensively used depends on the reference; intensive use of space is therefore a subjective assessment. We can make intensity an objective parameter by relating the space use of a plan to a clearly defined, general reference. A local reference for space use, such as a space use indicator for the area immediately surrounding the plan, offers an insight into the intensity of a site by comparison with its surroundings. However, while we can use a space indicator as an objective measure, our judgement will still depend on the context.

The concept of multiple land use is more objective; there is a clear difference between a plan with one function and a plan with multiple functions. However, we do need to define functions clearly to distinguish between multiple and singular use.

2.7 Benefits of multiple and intensive use of space

Optimising the use of space is a new challenge. If we can meet this challenge, it will be possible to economise on urban land use. There are other benefits to multiple and intensive use of space, beyond better utilisation of scarce space. We can divide these ‘other’ benefits into ‘financial’ and ‘public.’

40 Multiple and intensive use of space

2.7.1 Financial benefits Financial benefits from projects that make multiple and intensive use of space are reflected in an increase in land value. If we can build more square metres of property on a given piece of land, the value of that land increases. We can show this by a residual land value calculation. For instance, if new property brings in revenue of € 2 000 per square metre and it costs € 1 000 to build this square metre, the residual value of the land on which it is constructed is € 1 000 (€ 2 000 (revenue) minus € 1 000 (costs)). If we can build twice the number of square metres on the same piece of land, for the same construction cost per square metre, the revenue is € 4 000 and the costs are € 2 000. In that case, the same piece of land has a value of € 2 000. Optimising the use of land therefore generates benefits in terms of residual land value.

Given the above, intensive and multiple use of space also generates indirect value. If such projects are built to a high standard, the value of surrounding property and of the land on which this property is built may also increase. However, this indirect benefit accrues to others. Part of the added value is returned to the public purse via higher property tax revenues, through property transfer tax and through annual property tax. Other indirect benefits result from local economic developments. Projects involving multiple and intensive use of space on a scale larger than that of a single building can create extra employment and economic activity. Projects involving multiple and intensive use of space around a railway station can increase the number of passengers. This increases the revenue of public transport, thus creating indirect financial benefits. For large inner-city stations serving a large urban area, these extra revenues are limited in terms of percentage, but they can be substantial in absolute terms.

2.7.2 Public benefits Multiple and intensive use of space can have a positive effect on spatial quality. Hooimeijer et al. [2000] researched the elements of spatial quality in order to measure this effect. They used a matrix as a means of developing a common language. Schoonheid is geld (beauty is money) describes first steps towards financially quantifying the effects of spatial quality in public cost-benefit analyses [Dammers et al., 2005].

Multiple and intensive use of space may also have a positive effect on sustainability [Dobbel- steen & Wilde, 2004]. This effect takes a number of forms. Compact, high-density projects can use smaller amounts of building materials for the same number of square metres of property. This reduces both the building costs and the environmental impact of new property. Multiple and intensive use of space can also reduce energy consumption, in that some of the heat lost from one building can be recovered by another. For instance, modern offices produce more warmth than they need, whereas flats need more heating than cooling. Mixing these functions can bring energy use into equilibrium. Newman and Kenworthy [2001] found that the intensive use of space led to reduced per capita consumption of fuel for transportation. Mixing functions reduces the need for transport still further. People can live and work in the same district, and there are peak travelling times in both directions, ensuring more efficient use of the transport system. Finally, saving rural areas is also an important contribution to sustainability.

Making multiple and intensive use of space near infrastructure enhances the accessibility of the city. If the location is readily accessible, transport will be used more efficiently and

41 Rail Estate

the costs will be lower, in both financial and environmental terms. Siting projects involving multiple and intensive use of land near to public transport systems stimulates use of those systems, which is in the public interest.

2.8 Conclusion

Cities have shown major growth over the last 50 years, mainly in the form of suburbanisation. This growth has led to mono-functional, low density urban sprawl. Consequently, rural landscape is becoming rare around many cities. These surroundings must therefore be protected against urban expansion. For the Dutch situation, it is important to make a distinction between a local and a national space shortage. The Netherlands is the most densely populated country in the European Union, but its cities are not as densely populated as London and Paris. Pressure on space, together with the issue of spatial quality, mean that the need for ambitious inner-city projects involving multiple and intensive use of space is still as urgent as elsewhere in Europe.

Multiple and intensive use of space are spatial planning concepts that can optimise the use of space in inner cities. The most important difference between the two concepts is that multiple use of space focuses on combining different functions within a certain space, whereas intensive use of space focuses on density. Multiple use of space is an objective notion, in that we can easily see whether a given space has more than one function. Intensity or density is a relative notion and hence more subjective. However, we can measure intensity objectively by comparing a project with its direct surroundings on the same scale or with land use on the site before the project. In practice, multiple and intensive use of space are often combined. There are a number of strategies for optimising the use of space by multiple and intensive use. These strategies involve the second (surface), third (height) and fourth (time) dimensions, and combinations of these dimensions are possible. The various strategies can also be adopted at different scales, such as floor surface, the building on its site and complete urban districts.

Because multiple and intensive use of space are common in every city, it is not possible to specify the extent to which either concept is applied. This will depend on the size of the area studied and the surroundings at that scale. For the purposes of this research, we shall define a combination of functions within an urban plan as multiple use of space and an urban plan with a higher floor space index than its surroundings on the same scale as intensive use of space.

Multiple and intensive use of space can generate important financial and social benefits, quite apart from more efficient use of space. Financial benefits can arise from higher land value, partly resulting from increased spatial quality. Public benefits also accrue from the increased spatial quality that results from projects involving multiple and intensive use of land. Such projects can also enhance urban sustainability in general.

This thesis will focus on projects involving multiple and intensive of space near – and especially over – railway infrastructure. Chapter 3 will deal with the development and redevelopment of station areas and their boundary conditions and Chapter 4 will give an overview of relevant international reference projects.

42 Introduction

Chapter 3 Railway stations and railway areas

The location and typology of the railway station, buildings and infrastructure have a major effect on the surrounding area and on the scope for implementing the different forms of multiple and intensive use of space discussed in the previous chapter. Sections 3.2 to 3.4 will discuss different types of station, different functional arrangements within stations and different vertical track positions in stations. Section 3.5 will address the cohesion between these elements and how the typology of the station affects the options available for developing property over the track. Section 3.6 will look at the different types of land around railway stations. Finally, Sections 3.7 and 3.8 will examine possible urban densities and mixtures of functions, as introduced in the previous chapter. First, however, we shall look at the background and statistics concerning recent developments in railway infrastructure and railway traffic, and their consequences for property development.

3.1 A renaissance of public transport?

Throughout Europe, railway stations and their surrounding areas are being redeveloped, both to accommodate high speed railway lines and because of a lack of inner-city sites. This redevelopment has led to a growing interest in public transport, as it is difficult for other forms of transport to reach city centres. The redevelopment of stations and their surroundings has given stations an even more pivotal role. Indeed, they influence the very nature of the city, with Von Gerkan subtitling his book on the renaissance of railway stations ‘The city in the 21st century’ [Gerkan, 1996]. The oft-quoted strengths of rail are that it is relatively environment-friendly, safe and reliable. Its weaknesses are its lack of flexibility, its generally unattractive and cumbersome organisation and – with a few exceptions – its poor performance and image [Bertolini & Spit, 1998]. It is important to so develop station areas as to use the strengths of the railway and counteract its weaknesses.

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3.1.1 Railway transport and infrastructure: some statistics To identify trends in railway transport, we have compared the growth of transport by train in Belgium, France, Germany, the Netherlands and the United Kingdom between 1995 and 2002 [Eurostat, 2005]. There was an increase in the number of kilometres travelled in all countries – except the Netherlands. As access to cities by car becomes more difficult, public transport will play an increasingly important role in inner-city redevelopment projects. This trend is likely to continue. For instance, 82% of commuters working in the office development at Canary Wharf in London use public transport [Canary Wharf Group plc, 2002]. If public transport is to play this role to the full, it must become more comfortable and acquire more capacity.

Rail passenger transport 80 000 < Growth of Germany passenger 70 000 transport between

60 000 1995 and 2002 France [source: Eurostat, 50 000 2005]

40 000 United Kingdom 30 000

Million passenger kilometers 20 000

Netherlands 10 000 Belgium 0 1995 1996 1997 1998 1999 2000 2001 2002 Year

We can also compare the change in length of the railway and motorway networks. Such a comparison shows that the network available to cars has been growing, while the rail network has been shrinking [Eurostat, 2002]. As a consequence, railway lines are being used more intensively.

Railway network 50 000 < Length of the railway Germany network in five 40 000 European countries France [source: Eurostat, 30 000 2002]

Length [km] 20 000 United Kingdom

10 000

Belgium Netherlands 0 1990 1999 Year

Railway stations and railway areas < Motorway network Length of 12 000 the motorway Germany network in five 10 000 European countries [source: Eurostat, 2002] 8 000 France

6 000 Length [km]

4 000 United Kingdom

Netherlands 2 000 Belgium

0 1995 2002 Year

3.1.2 The advantages of rail transport Bertolini and Spit sum up the advantages of transport by rail in Cities on Rails [1998]: land use, chemical pollution, energy consumption, safety, environmental and social costs. The data below are taken from this research.

Land consumption: In France, 1 000 passenger km by train requires 3.2 m2, while the same number of passenger km by car requires 15 m2. This is a factor of 5, and similar numbers have been calculated for Germany. Chemical pollution: In Germany, road transport pollutes 8 times as much per unit transported as does rail transport. Energy consumption: Car travel consumes 2.7 times as much energy per passenger km as does rail. Safety: The figure below illustrates the difference in safety between car and train [Eurostat, 2000]. In the 15 countries of the EU as it was in 2000, the number of deaths per kilometre travelled is 20 to 30 times

higher in the case of car travel. < Deaths per thousand million km travelled 16,0 Deaths per Car EU-15 d thousand million 14,0 pkm travelled 12,0 [source: Eurostat, 2000] 10,0 Car Netherlands 8,0

6,0

4,0

2,0 Rail EU-15 Rail Netherlands Deaths per 1 000 million km travelle 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 Year

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Environmental In the case of Germany, the internalisation of social costs (accidents, and social costs: traffic jams, air pollution and noise), would have amounted to € 30.4 per 1 000 passenger km for road and € 1.65 per 1 000 passenger km for rail. This is a factor of 18, and other research indicates the same general picture.

3.1.3 Density of railway infrastructure The Dutch motorway network is the densest in Europe [Eurostat, 2002]. On the other hand, the density of the Dutch rail network is moderate by comparison with that of other countries. The figure below compares railway density in kilometres per 1 000 square kilometres of land in Belgium, Germany, France, the Netherlands and the United Kingdom [Eurostat, 2002].

Rail network density (1999)

Belgium < Rail network densities for Germany five European countries [source:

United Kingdom Eurostat, 2002]

Netherlands

France

0 20 40 60 80 100 120

Density [km/1 000 km2]

The utilisation of the railway networks in different countries has also been compared, show- ing the Dutch situation to be atypical. This difference is an important factor with respect to building projects near and over railway tracks. Because of the intensity with which the Dutch network is used, the consequences of disrupting train operations are more severe than on less intensively used networks. Given the Dutch situation, projects involving construction over railway tracks will be subject to more severe restrictions, as it is more important to keep the network available.

Rail network utilisation (1999)

Netherlands < Rail network utilisation in

United Kingdom five European countries [source: Eurostat, 2002] Belgium

France

Germany

0 1 2 3 4 5 6

Utilisation [million passenger kilometres/km]

46 Railway stations and railway areas

3.2 Types of railway station

Cities on Rails [Bertolini & Spit] describes the station as a geographical entity with two identi- ties. On the one hand, the railway station is a node in a network of trains and other transport modes. On the other hand it is a place in the city, with a concentration of infrastructure and a group of buildings and open spaces. Building close to railway infrastructure reduces the scope for expanding the capacity of that infrastructure. However, such construction enhances the attractiveness of the area. Developing offices and dwellings is particularly desirable, due to the accessibility of the location. Shops and leisure facilities should also be part of the development. The large number of passengers and passing pedestrians will lead to high rents per square metre for retail premises. Shops and leisure are also a means of attracting people to the station area, especially outside peak hours. This can enable better use of the space over time.

Nederlandse Spoorwegen (NS, Dutch Railways) have divided railway stations into six types [NS Commercie, 2001]. Stations are categorised by their position relative to the city centre and by the types of train that serve them. The position with regard to the city centre is classified as: within the city centre, at the city boundary and outside the city boundary. The different types of train are: high speed train (HST), intercity and stopping train. The table below shows the different types of station, with Dutch examples.

Functions of railway stations

Type 1: Very large station in the centre of a large city Types of train: All. Examples: Amsterdam Centraal, Rotterdam Centraal, Den Haag Centraal and Utrecht Centraal.

Type 2: Large station in the centre of a middle sized city Types of train: Intercity and stopping. Examples: Leiden, Dordrecht and ’s-Hertogenbosch.

Type 3: Suburban station Types of train: Intercity and stopping. Examples: Duivendrecht, Amsterdam Sloterdijk and Rotterdam Alexander.

Type 4: Station in a small town or village Types of train: Stopping. Examples: Maarssen, Purmerend, Woerden and Boxtel.

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Type 5: Suburban station with departure function Types of train: Stopping. Examples: Amersfoort Schothorst, Amsterdam Muiderpoort and Delft Zuid.

Type 6: Station outside a small town or village Types of train: Stopping. Examples: Abcoude, Breukelen and Putten.

The present study primarily discusses station types 1 to 3, as redevelopment of the station area, including development of property over the tracks due to lack of space, generally occurs at this type of station. These stations are located in urban environments and form public transport nodes. Study of international reference projects involving multiple use of space in station areas will also focus on these types.

3.3 Functional arrangements of stations

Railway stations take a number of forms and can be classified according to their functional arrangement. We shall analyse the various possible functional arrangements below in terms of the way they influence transport logistics and urban development. The three types are terminus stations, through stations and cross stations [Krings, 1985 and Vákár & Snijder, 2001].

3.3.1 Terminus stations Terminus stations have the simplest form. As their name implies, they lie at the end of a railway line. Trains use the tracks in a terminus station twice, as they enter in one direction and leave in the other. If a train changes direction, it will have to negotiate one or more switches to reach the appropriate track.

In a through station, the train continues its journey without changing direction. A second train can use the platform shortly after the first has left. This arrangement uses urban space more efficiently. For a given train handling capacity, a terminus station needs a larger number of platforms than a through station and hence occupies more inner city space. A terminus station is also less than ideal for passengers, unless they are starting or ending their journey, as changing trains takes longer. This is still the case if they continue their journey by the same train, as the train will stay in the station for longer.

The Netherlands has relatively few terminus stations. In the western part of the country, the only inner-city terminus station is Den Haag Centraal. Outside the Netherlands, terminus stations are often found in large cities. All major railway stations in London and Paris are terminus stations. Examples include the Gare du Nord and the Gare Montparnasse in Paris,

48 Introduction

Den Haag Centraal Functional

arrangement of a terminus station <

and Liverpool Street and St Pancras in London. The large stations in Germany where redevelopment that includes large scale urban development is under discussion are also terminus stations. Examples include Stuttgart, Frankfurt and Munich. The redevelopment plans for these stations all include moving the tracks under ground, transforming the terminus station into a through station, for reasons of logistics and space. Antwerpen Centraal recently underwent a reconstruction operation of this nature.

The building at the end of the platforms in a terminus station – the main entrance – is often an urban landmark. The connection between the city and the transport system is direct and efficient; passengers are guided from the concourse end of the platforms to their trains and tend to wait on the concourse rather than on the platform itself.

3.3.2 Through stations The tracks through the station divide the urban fabric. Unlike terminus stations, which are oriented directly towards the city centre, the tracks of through stations run parallel to the boundary of the city centre. Today, these stations lie in city centres, as the cities have expanded around them. As a consequence, through stations have two entrances and passengers are guided to the platforms via a subway or a bridge. An important drawback of having two entrances is that in most cases one side is less attractive than the other. The ‘good’ entrance is the one most used, and is located on the side nearest the historic centre of the city. The more neglected entrance functions as a ‘back door’. The back entrances of Rotterdam Centraal and Delft Stations are examples of this phenomenon.

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’s-Hertogenbosch Functional arrangement of a through station < [Aeroview]

< Duivendrecht Functional arrangement of a cross station [Aeroview]

50 Railway stations and railway areas

Through stations are common in the Netherlands. When the railway infrastructure was built, most cities were small enough for the railway infrastructure to be located along the city borders, at walking distance from the city centre. The tracks and platforms of a through station can be used more intensively than those of a terminus, and fewer tracks are needed. Through stations therefore consume less space in the city centre. In addition, changing trains is more efficient than in a terminus station.

3.3.3 Cross stations Cross stations are a special type of station. They are so sited as to link intersecting railway lines and hence enable passengers to change quickly from one line to another. This is their most important function, but as the land around them gets developed they also become points of arrival and departure. One drawback of this functional arrangement, if the station is above ground, is that it divides the land into four parts, which disrupts the continuity of the urban fabric. An advantage by comparison with the other functional arrangements is that trains on the two lines do not interfere with each other.

Duivendrecht and Amsterdam Sloterdijk Stations on the outskirts of Amsterdam are examples of cross stations, as is Lehrter Bahnhof in Berlin. In the case of Lehrter Bahnhof, one direction runs underground, so that this cross station only splits the urban fabric into two parts rather than four.

3.3.4 Consequences for urban development Cross stations pose the most problems for development of the railway station area. They divide the land into four parts and the large number of crossings limits the options for building over the tracks.

Through stations divide the urban fabric into two parts. Although one of these parts will generally have less spatial quality than the other, urban development is easier than at cross stations. Building over the tracks may be slightly easier than for a cross station, as long as enough tracks are available. If they are, it may be possible to take some tracks out of service while using the others more intensively during construction work.

Terminus stations are the most convenient arrangement for urban development, as development can take place around the station and is not divided by infrastructure over its full length. Over-track building is also easier, as taking tracks out of service at a terminus station generally causes less disruption than at other types of station. Temporary track closures at a terminus station only disrupt operations at the station itself, not at others on the line. This contrasts with the situation at through stations, where train movements are affected in both directions.

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Underground Subsurface Ground level Elevated

< Four vertical track positions

3.4 Vertical position of station tracks

We can categorise railway stations not only by there funcional arrangements but also according to the vertical position of the tracks. The vertical position also affects station development plans. We can divide vertical track position into underground, subsurface, ground level and elevated. The four types will be discussed in the following sub sections.

3.4.1 Underground The reason for not putting tracks under ground in the past was that underground construction is complex and expensive. Examples of underground railway stations are therefore relatively new. They include Rotterdam Blaak and part of Antwerpen Centraal (under construction). Good reasons for investing in placing tracks under ground are the opportunity this gives to upgrade the railway system (eliminating crossing traffic) and to remove the barrier that tracks create in a city. Underground tracks allow other traffic to cross the line unhindered, and noise and vibration no longer stand in the way of urban development. When the tracks lie deep underground, however, the connection with street level can be a problem.

3.4.2 Subsurface Underground Subsurface tracks differ from underground tracks in that they have a more direct relation- tracks at ship with the city. Rijswijk and Schiphol Stations are examples of this type. Liverpool Street Rotterdam Blaak was moved to below street level 100 years ago. Because of the direct relationship with [F. van Dam] street level, these stations are very accessible and changing to other forms of transport is < < easy. They automatically become multilayered public transport hubs. Subsurface tracks at Rijswijk <

52 <

Tracks at ground 3.4.3 Ground level level near When tracks lie at ground level, the difference between terminus stations and through Den Haag Centraal stations is important. Access to a terminus station from the city centre side is good if the

< < < station is at ground level, as there is no difference in height between street level and platform Elevated tracks level. In through stations at ground level, passengers can only reach the platforms in the at Amsterdam middle by overcoming the height difference twice, via a subway or bridge. For this reason, Lelylaan most terminus stations have remained at ground level, whereas the tracks and platforms of many through stations in the Netherlands have been elevated.

3.4.4 Elevated As mentioned above, many through stations have elevated tracks. Elevating the tracks makes platforms more accessible and facilitates movement between the parts of the city either side of the station. However, elevated tracks do form a major visual barrier. Transfer to other forms of transport is generally at ground level, in front of or under the tracks. The station building is located in front of the tracks, as a facade and landmark. The tracks at Amsterdam Lelylaan are elevated up to 6 m above ground level. The station building is located under the tracks and the trains can be seen from the city. Placing the station building under the tracks gives both station entrances a similar spatial quality.

3.4.5 Consequences for urban development Underground and subsurface tracks are the most convenient when it comes to building around the station or over the tracks. Although they are costly, these tracks do not form a barrier in the city and buildings sited over the tracks have a direct entrance at ground level.

Elevated tracks do form a barrier because of noise, but they do not form a functional barrier to traffic. It is easier to build over ground level tracks than elevated, as the supporting structure has less height to compensate for.

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Terminus station Through station Cross station < Typology of Underground Rotterdam Blaak railway stations

Subsurface Rijswijk Schiphol Ground level ’s-Hertogenbosch

Elevated Amsterdam Centraal Rotterdam Centraal

3.5 Typology of railway stations

We can combine the different functional arrangements and vertical track positions at stations in a matrix that gives the different possible typologies of railway stations. The combination of functional arrangement and vertical track position largely determines the way we can develop the station and its surrounding area, and the options for building over the tracks. Building is most difficult over elevated tracks and easiest over underground tracks. Cross stations are more difficult to build over than through stations. Building over the tracks is easiest at terminus stations. The matrix gives examples of stations in each category, indicating the relative difficulty of building over the tracks at each type of station.

Local urban transport is linked to railway infrastructure. Stations connect relatively long distance transport by train with the underlying infrastructure of metro, tram and bus. Large stations will have a substantial number of local transport modes that must be integrated into the station programme. This study will not discuss these relations and their typology further, but it is important to take local public transport into account in station development. Local public transport modes are also easier to build over. There are many examples of buildings over bus and metro stations. Together, they form part of the total development or redevelopment plan for the station area.

3.6 Different types of land near railway infrastructure

There are different types of land near tracks where property can be developed. Railned (part of Dutch rail network manager ProRail) calculated that there are 40 000 hectares of land near tracks for which there are no development plans [Brandsma, 2001]. According to the Ministry of Housing, Spatial Planning and the Environment, Dutch society will demand about 110 000 hectares for offices and housing between now and 2020 [H+N+S, 2002]. This means that the amount of available space near tracks is really substantial. Originally, property development took place in four phases: in front of the station (1), towards the city centre (2), behind the station (3) and on land away from the station (4). New development near railway infrastructure takes place alongside the tracks. Where a strip of land is available between the tracks and existing buildings, it is relatively easy to develop new buildings. Examples are to be found in Groningen and Amersfoort.

54 <

Development Tracks often fan out as they emerge from the station, leaving large open spaces. These along the tracks at spaces are sparsely occupied by railway-related buildings, railway yards and low-quality Amersfoort Station industry. They lie close to the city centre and have huge development potential compared

< < < to the narrow strips available beside the tracks. The main difference between these and Development other open spaces in the city centre, such as parks and squares, is that they contribute along the tracks at nothing to the spatial quality of the city. Redevelopment therefore offers interesting potential. Groningen Station There are examples of open spaces near tracks in urban areas in Rotterdam, Utrecht, Haarlem and Amersfoort. Amersfoort Yard, for instance, covers about 65 hectares [Studieconsortium Rail-Locatie-Ontwikkeling, 2001]. When a railway yard moves or is covered over, it becomes possible to develop the land, adding a complete district to the city. The King’s Cross Railway Lands in London are comparable in size to Amersfoort Yard (approximately 50 hectares) and lie between the tracks of King’s Cross and St Pancras Stations [Quantrill, 1999]. Seine Rive Gauche, on the left bank of the Seine in Paris, was developed by clearing 130 hectares of tracks within the Boulevard Périphérique [Pousse, 1999].

Major property developments in station areas will be so planned as to make both multiple

Amersfoort Yard and intensive use of space. We discussed multiple and intensive use of space in the previous < < < chapter; in multiple use the same space has more than one function, while intensive use occurs where there is a high level of urban density. In the following sections we shall use a King’s Cross Railway Lands study of international projects to show how a number of large scale developments near rail- [Davies] way infrastructure have achieved high density and multiple functionality. <

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3.7 Urban density: intensive use of space

It is important to allocate the right amount of space to property development. The station area should be neither overcrowded nor under-utilised. We can measure the density of a station area in terms of floor space index (FSI), a concept introduced in Chapter 2. In general, Dutch planners aim for an FSI of 0.3 to 0.5, i.e. 3 000 to 5 000 m2 of property per hectare of land [Koolhaas et al., 1997 and Berghauser Pont et al., 2002]. A number of major station area developments have been undertaken around Europe, or are at the construction or planning stage. Six of these projects have been assessed on their use of space [Wilde & Dobbelsteen, 2004]. The average density is 1.47, which is quite high compared to standard urban density. When planning such projects, it is important to adjust their density to that of the surroundings. The examples from the study give an interesting insight into the densities possible in station areas.

Density of station area 3 000 000 < Densities of La Défense recent development

] 2 500 000 2 projects centred 2 000 000 Amsterdam Zuidas on public y = 1.47x Rive Gauche transport nodes 1 500 000 Canary Wharf 1 000 000 Amsterdam Bijlmer Broadgate Total gross floor area [m 500 000

0 0 400 000 800 000 1 200 000 1 600 000 2 000 000

Ground area [m2]

3.8 Mixing functions: multiple use of space

Station area redevelopment can combine different functions. The six projects mentioned above were analysed to gain an insight into the possible proportions of different functions within a station development project. A distinction was made between offices, homes and other functions [Wilde & Dobbelsteen, 2004]. The results show that offices still account for the largest percentage of developments. Some projects consisted almost entirely of offices, while others attempted to create a mixture of functions.

Division of floor space between functions 2 500 000 < Combinations of Offices Dwellings functions in recent ]

2 Other 2 000 000 development projects centred on public 1 500 000 transport nodes

1 000 000

500 000 Gross floor area per function [m

0 Broadgate Canary Wharf Amsterdam Bijlmer Rive Gauche La Défense Amsterdam Zuidas

Project

56 Railway stations and railway areas

3.9 Conclusion

Statistical analysis shows the train to have some substantial advantages compared to the car. Such analysis also reveals that the rail network has shrunk slightly, while the network available to cars has grown substantially over the last years. Combined with a growing number of passengers for railway transport, this leads to more intensive use of railway infrastructure, putting more pressure on its availability and reliability. The Dutch network is extremely intensively used by comparison with other European networks, leading to even higher demands on capacity and availability. These demands impose severe restrictions on projects involving building over tracks, and it is necessary to take account of these constraints.

The type of station governs the options for property development in the station area, especially for over-track construction. We can classify stations according to their functional arrangement and the vertical position of the tracks. A station conforms to one of three functional arrangements: terminus, through or cross. For passenger transport and efficient use of space, cross stations are the most efficient and terminus stations the least so. On the other hand, it is cheaper to build over and near the tracks of terminus stations than at through or cross stations. We divide vertical track position into underground, subsurface, surface and elevated. Underground and subsurface stations are the most practical when it comes to developing property over and around the track, as they do not impinge on the urban fabric. Elevated tracks are the least suitable for over-track construction.

The land around railway infrastructure is also of different types. The strips of land alongside tracks are easy to develop, and hence are among the first to be developed. Where tracks fan out on emerging from the station, they create large, potentially useful pieces of land, which are generally occupied by railway-related functions and low-quality infrastructure. It makes sense to develop such railway land into high-quality urban projects making multiple, intensive use of space and offering good accessibility. When we examine the density and multiplicity of functions on such pieces of land, we find that they are often used intensively. There is less multiple use of space, however, as the projects compared generally involve a high percentage of offices and limited housing. The next chapter will examine international reference projects in station areas that involve building over the railway infrastructure. We shall analyse and compare station typology, historical background and the intensive and multiple use of space.

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58 Introduction

Chapter 4 Reference projects

Chapter 2 addressed the principles of multiple and intensive use of space, while Chapter 3 looked at the background of station area development/redevelopment and station typologies. The present chapter deals with reference projects involving multiple and intensive use of space in station areas. A survey of reference projects will give an insight into the multiple and intensive use of space in station areas and the latest methods for building over railway tracks. The chapter will start with examples of projects in New York, Melbourne and Tokyo, before moving on to a general overview of reference projects in Western Europe. We shall then use a set of selection criteria to choose some of these Western European reference projects for closer examination. The chapter will conclude with an analysis of the similarities and differences between the selected reference projects, focusing on differences by comparison with the Netherlands.

4.1 Projects outside Europe

All over the world, large inner-city stations have been redeveloped in combination with urban restructuring. Building over railway infrastructure is equally international. Although the present thesis concentrates on Western Europe, and the Dutch situation in particular, this section will discuss three reference projects from other continents, to place construction over railway infrastructure in a broader context.

4.1.1 Grand Central Terminal, New York We shall start with the oldest and most famous example of building over railways: New York’s Grand Central Terminal. At the end of the nineteenth century, the yard of Grand Central was one of the most crowded in the country and radical improvements were needed [Belle & Lighton, 2000]. In October 1899 a construction process had begun that would not interfere with railway operations, the aim being to create a safer and more efficient layout. But even after reconstruction, the problems of overcrowding and safety remained major concerns.

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< The congested rail yards of New York Central around 1900: crowded, unsafe and smoky [MTA/Metro North Collection]

In addition, the smoke from the stream trains was a great nuisance in the centre of such a densely populated area. A collision in 1902 caused many deaths and injuries, becoming a catalyst for major change [Belle & Lighton, 2000].

In 1902, the Chief Engineer of New York Central, William Wilgus, developed a comprehensive solution to the problems of railway transport in the heart of the city. The new electric technology made the entire Grand Central project possible [Schlichting, 2001]. The railway system would change over to electric traction to solve the problem of air quality. The tracks A 1913 could then be dropped to make room for buildings that would pay for the costs of this trans- photograph of formation. Wilgus wanted to utilise the ‘air rights’ over the railway infrastructure. Even in Park Avenue with the newly those days, these air rights were considered very valuable and it would be possible to develop built city streets about 20 hectares of surface. The project was to shape modern skyscraper development in over the railway midtown Manhattan [Belle & Lighton, 2000]. By March 1903, a solid plan had been drawn infrastructure up for a 57-track, all-electric, double-level terminal. Wilgus even included underground loop [Columbia University] tracks to eliminate part of the problem of trains arriving and departing at a terminal station < < [Schlichting, 2001]. Grand Central Terminal was designed to handle 100 000 000 passen- An aerial gers per year. Annual traffic peaked at 65 000 000 passengers in 1947, before the advent photograph of airline and car travel [Schlichting, 2001]. of the concept of air rights When Grand Central Terminal opened in 1913, half of the air right sites were already built on for a new city over the railway or at the planning stage. Wilgus succeeded in raising 3% of the total project costs per year. infrastructure The new district over the tracks was dubbed Terminal City, with offices, apartment build- [William D. ings and hotels. Following the Terminal’s completion, four large hotels were built on the air Middleton] <

60 Reference projects

right sites, with a total of 5 000 rooms. These hotels set the standard for modern comfort and luxurious surroundings, and included the famous Waldorf-Astoria hotel [Belle & Lighton, 2000]. The Waldorf-Astoria also had numerous linkages with Grand Central, which made it a prime example of the Terminal City concept.

4.1.2 Federation Square, Melbourne Melbourne also has an example of building over railway infrastructure. The Federation Square project is a complete city district built over a railway yard and forms the cultural heart of the city. Federation Square opened in 2002 and since that time has become the number one destination for international tourists and for events and activities in the State of Victoria [Federation Square, 2006].

The Federation Square development started in reaction to the long-standing recognition that Melbourne lacked a true civic centre [Misiak, 2005]. An international design competition was held for development over the railway yard in 1996. It was even hoped that the results of the competition would rival the Sydney Opera House. The winners were a combination of Lab Architecture Studio and Bates Smart architects.

Federation Square < The project was initiated by the State of lies over a railway Victoria and financially supported by the City yard, between Melbourne’s of Melbourne, the Commonwealth Govern- central business ment and private investors. Cost estimates district and the fluctuated between AUD 110 and 150 million Yarra river (€ 66 to € 90 million) [Misiak, 2005]. [Cissée]

The entire over-track site occupies about 3.6 hectares, with an elevated deck supporting the buildings. The central square over the tracks is designed to hold up to 20 000 people. The buildings around the square form a series of innovative structures, using a variety of materials. The project was budgeted at AUD 110-150 million, but finally cost AUD 450 million (€ 270 million). The project should have been ready in time for the 2001 Centennial Commemoration of the establish- ment of the Australian Federation, but in fact was only completed in 2002 [Misiak, 2006].

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The deck over the tracks is supported < The Federation by 4 000 vibration-absorbing springs. Good Square project is constructed vibration and noise isolation was needed directly over the because the buildings include radio and tel- tracks [NLA] evision studios, plus two museums. The deck alone cost AUD 64 million, which was one of the first indications that the project would go well over budget.

Although the project had some major problems, the result is an impressive building over tracks that also proved that Melbourne’s central business district could be connected to the Yarra river and simultaneously form the new cultural heart of the city.

4.1.3 Shinjuku Station, Tokyo Shinjuku Station in Tokyo opened in 1885 and is now the world’s busiest station. An average of 2.9 million passengers use the station every day. For comparison, the Netherlands’ busiest railway station, Utrecht Centraal, handles about 150 000 passengers daily, which is only 5% of the number using Shinjuku. Because there is little information on this project in the literature, most information comes from Paul Chorus, a Dutch PhD student in Tokyo.

Shinjuku Station lies on the Yamanote line, a circle line for commuters that connects all of Tokyo’s major stations. The loop was completed in 1925 and the Yamanote line carries an average of 3.6 million passengers a day [Tiry, 1997]. The line is 35 km long and a complete circuit takes about an hour. The line is playing an important role in the city’s move towards radical verticalisation linked with the emergence of new urban centres [Tiry, 1997]. The area around Shinjuku Station is one of these. Because Japan Railways Group (JR) only owns the land on which the stations stand, they focus on maximising use of the existing station areas. The space over the tracks has been utilised by building the station area on bridges, to form a multilevel structure with a diversity of business functions [Tiry, 1997].

< Shinjuku Station area. The motorway over the tracks (Koshu Kaido Avenue) is elevated and a platform has been constructed over the tracks on the south side of the existing station building.

62 Introduction <

The platform The motorway over the tracks at Shinjuku Station (Koshu Kaido avenue) is elevated. A bus over the tracks of station has also been built over the tracks. There was already a bus station on the west side Shinjuku Station of the station, but this no longer met requirements. Both projects are being developed by is already under construction the Ministry of Land, Infrastructure and Transport. The railway lands are owned by JR East

[Paul Chorus] (East Japan Railway Company). To compensate for the development potential lost by con- < < < struction of the bus terminal, JR East will be allowed to build higher structures than permitted in the local zoning plan. The platform over the tracks will have a surface of about A platform 2 2 over the sidings 18 500 m and will carry about 26 000 m of property. Shinjuku Station demonstrates that at Shinjuku Station, building over railway infrastructure is possible even over the world’s busiest railway station. with a bus station and development project [Paul Chorus] 4.2 Projects in Western Europe

As discussed in earlier chapters, there are many station redevelopments under way in West- ern Europe, partly due to construction of the high-speed network. Many of these projects The Katreinetoren include buildings over or very close to the tracks. The section below will give a brief overview over the tracks at

Utrecht Centraal of Western European projects. < < <

4.2.1 The Netherlands The Orient The Netherlands has two locations at which buildings have been erected over railway tracks: Express apartment building above offices and dwellings at Rijswijk Station and the Katreinetoren over Utrecht Centraal. Con- Rijswijk Station struction of the HSL-Zuid and associated stations prompted plans for six ‘key projects’: <

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Amsterdam Zuidas, Rotterdam Centraal, Den Haag Centraal, Utrecht Centraal, Arnhem New building Station and Breda Station. All of these projects included plans for building over the tracks adjacent to Brussel-Zuid at some stage of the design, except for Arnhem Station, which has buildings close to the Station track. Plans are still under way for all projects, but building over the tracks is now only being considered only in the cases of Den Haag and the Zuidas. Construction over tracks is also < < under consideration for smaller stations. Examples include a library over Zaandam Station Reconstruction of and buildings above the future railway tunnel through Delft. Antwerpen-Centraal with new tracks at Levels -1 and -2 4.2.2 Belgium Two large projects involving urban redevelopment and railway infrastructure are of interest in Belgium. Recent developments in Antwerp are interesting from a technical point of view. The new tracks for the high-speed train will pass under the existing terminus station and will partly change it into a through station. The station will comprise four levels: four through tracks at -2, four tail tracks at -1, the concourse at ground level and six tail tracks at +1 (the level of the existing tracks). The area around Antwerpen-Centraal is also part of the development [Buyten, 1992]. A major urban redevelopment programme is being developed around Brussel-Zuid [NMBS, 2001]. Like Antwerp, this station is part of the high-speed network. The new buildings here are close to the tracks, rather than overhead.

4.2.3 Germany Deutsche Bahn (DB) has been working on Projekte 21, which is intended to make rail transport more attractive. The programme includes upgrading stations for the 21st century. DB is working with local authorities to integrate stations into their urban surroundings [Gerkan, 1996] and integrating the high-speed network plays an important role.

Plans have been made for large stations such as Stuttgart, Frankfurt, Munich and Berlin [Ger- kan, 1997]. Lehrter Bahnhof will become Berlin’s central station and will also be transformed into a cross station. These four projects include completely reorganising the tracks, changing over from ground level tail tracks to underground through tracks. Transforming these stations into through stations will free up large areas of railway land, which will be occupied by urban development. The illustrations below show this process for Frankfurt Hauptbahnhof. The total floor area planned in Stuttgart, Frankfurt and Munich ranges from 1.3 to 2.0 million m2.

64 Introduction <

The surroundings 4.2.4 England of Frankfurt Haupt- London has a large number of terminus stations that date from the second half of the bahnhof at present nineteenth century. Some of these border the City of London. The lack of available build- [M. Stumpfe] ing space in the City, together with the consequences of privatisation for British Rail’s

< < < financial position in the 1980s, led to exploitation of the land around the stations and the Future air-rights above them. redevelopment plans for Frankfurt A number of projects were undertaken at the perimeter of the City of London: Broadgate Hauptbahnhof [von Gerkan, (around and above Liverpool Street Station, 1991), Fenchurch Street, Cannon Street and Marg und Partner] Blackfriars. Elsewhere in London, there have been projects at Charing Cross, Victoria, Waterloo, Paddington and the King’s Cross Railway Lands. 42 000 m2 of offices have been built above the platforms of Charing Cross Station [Spring, 1991; Binney, 1992] and 50 000 m2 of offices and shops have been built above the platforms of Victoria Station [Edwards, 1997].

Buildings over Waterloo International Terminal was built next to the existing station, with a car park Cannon Street underneath. A number of existing buildings had to be demolished to make way for the

Station < < < new terminal. Plans were drawn up for Paddington Station [Rogers, 1990] and for the King’s Cross Railway Lands, but these have not been implemented and new plans are in 2 42 000 m of the pipeline. building over Charing Cross Station <

65 Rail Estate <

4.2.5 France Buildings over the Large-scale redevelopment projects for station areas are under way in Paris: Seine Rive new high-speed line at Lille Gauche and the Gare Montparnasse. The first involves redeveloping 130 hectares of rail- Europe Station way land near the Gare d’Austerlitz, in the centre of Paris, and includes construction of the National Library. At the Gare Montparnasse, the platforms have been covered over by a 3.5 < < hectare park and an office building [Südmeier, 1999]. New offices over the tracks of the Gare There are also projects involving multiple and intensive use space outside Paris. The con- Montparnasse struction of high-speed lines linking France with England and Belgium was an opportunity for in Paris the city of Lille to undertake a major development programme around a new station. This project also includes large buildings above the new high-speed rail infrastructure.

4.2.6 Other projects in Western European countries Redevelopment projects are also under way in other countries. A selection appears below [Studieconsortium Rail-Locatie-Ontwikkeling, 2001, Delcampo, 2001, Bertolini & Spit, 1998 and Garvelink, 2001]. They will not be discussed further within this research:

• Austria: Wien Hauptbahnhof (Vienna) • Czech Republic: Praha hlavní nádrazí (Prague) • Italy: Roma Termini (Rome) and Santa‹ Maria Novella (Florence) • Norway: Oslo Sentralstasjon (Oslo) • Poland: Warszawa Centralna (Warsaw) • Spain: Chamertín, Príncipe Pío and Atocha (Madrid) • Sweden: Stockholm City West • Switzerland: Luzern, Zürich and Basel

4.3 Selecting the reference projects

A number of criteria were used to select reference projects from the list above for further research. Project size is an important factor, as it is difficult to measure urban density in very small projects. An arbitrary minimum of 100 000 m2 was chosen. The projects selected had to include buildings above the track. Chapter 3 defined the various types of railway station, along with their effects on development of the station area. The list of reference projects

66 Reference projects

therefore had to include all possible functional arrangements and all vertical track positions. Finally, the selection had to include different project stages: completed, under construction and at the design stage. Including different project stages makes it possible to examine the functioning of completed plans, how they are executed and the latest knowledge and ideas on executing such projects. Plans that are still at a very early stage were not selected, as the information available regarding the structures was insufficient. The selection criteria are therefore as follows: • A minimum of 100 000 m2 of buildings have been built or are planned. • The project includes buildings above the track. • The selection includes all functional arrangements of railway stations: terminus station, through station and cross station. • The selection includes three different vertical track positions: underground/subsurface, ground level and elevated. • The selection includes different project phases: completed, under construction and at the design stage.

The table below lists major reference projects in Western Europe. The reference projects that meet the selection criteria are in blue.

Project Buildings Current Functional Track level(s) Meets above tracks situation arrangement criteria

Although Lille Europe meets the selection criteria, it will not be included, as it is not situated in an urban environment. The other projects are located in four different countries. All functional arrangements and vertical track positions are represented and all project phases are included. These six reference projects will be subjected to more detailed study.

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4.4 Research subjects Six reference projects have been selected for further analysis. Research criteria have been adopted, to allow clear comparison between the projects. These criteria are: origin, urban context, multiple and intensive use of space, structures and flexibility.

Origin We shall examine the origin of the project, to establish the main reasons for launching it. By comparing the projects, we should be able to identify general or specific factors that led to success, the parties involved and the period over which the project was or will be carried out. Urban context We shall consider the urban context of the project, to show how it fits into the city and the way in which it is arranged. This will include consideration of how the design adapts to the functional arrangement of the station and the vertical position of the tracks. Multiple and intensive use of space We shall assess the extent to which the projects make use of space, comparing different ways of making multiple or intensive use of space. The density of the project will be measured using the floor space index (FSI) introduced in Chapter 2. The FSI measures the ratio between the floor area created and the land surface on which it is built. It can be used at an early stage of a project, to estimate the floor area that can be fitted into the station area. The present study also deals with multiple use of space – the mixing of functions. We shall distinguish between offices, dwellings and other functions. ‘Other’ functions, such as shops, have been combined into one category because in most cases they make up only a small part of the project. Further analysis of specific details of these functions is not relevant to this study. Structures We shall discuss the types of structure built over the track, the position of structural elements on platforms or between tracks and current methods of over-track construction. Flexibility We shall examine the flexibility of the project, looking at the flexibility of the buildings and of the railway infrastructure. This will include the extent to which it will be possible to change or enlarge the structure in the future. Buildings have a planned life of 50 years or less, whereas railway infrastructure is intended to last over 100 years [Garvelink, 2001]. It is important to know whether it will be possible to modify the buildings during that period and, if so, how this can be done without interfering with railway operations. In addition, building over the railway infrastructure affects the options for expanding it.

The costs per square metre of buildings developed should also have been a research topic, but this had to be abandoned as the information available was limited and unreliable, and it was not possible to compare the costs of different projects.

68 Reference projects

4.5 London: Broadgate

Broadgate lies at the north-eastern border of the City of London, the financial centre, and is a good example of a station area redevelopment project. Complete restoration and renovation of the station itself was an important condition for the project. This was the first large-scale station redevelopment project in London. Work on the project started in 1985 and at completion in 1991 this was the largest office development project in the history of London [Hannay, 1985].

Broadgate: Buildings on the 4.5.1 Origin site of Broad Until the mid-1980s, the area in and around Liverpool Street Station was used exclusively Street Station for railway transport and included a large car park. At the time there was a great lack of are in grey, the marketable inner-city office space. British Rail (BR) had just been privatised, and govern- complex building over the tracks ment cut-backs forced the railway to sell attractive pieces of land. BR worked with private in blue. The companies, tracks were taken out of service, platforms were built over and every square renovated roof is millimetre of land was exploited commercially [Hannay, 1991]. indicated in white. [Stanhope

Rosehaugh] The Broadgate project at Liverpool Street Station was one result of this policy. Arup < < < Architects produced a design for BR and developer Rosehaugh Stanhope Developments. The project involved close cooperation between public and private parties. Liverpool Street Overview of Station (1875) and the Victorian Great Eastern Hotel (1884) were saved from demoli- Liverpool Street tion [Derbyshire, 1991]. Broad Street Station (1866), provided a freight service, but was Station before demolished as it was little used by this stage [Hannay, 1988]. The land previously occu- redevelopment pied by Broad Street was used for traditional office development. This generated funds for [Greater London Photograph the renovation of Liverpool Street Station and the more complex buildings over the railway Library] infrastructure. <

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4.5.2 Urban context Liverpool Street Station itself is a combination of two stations. The integration of Broadgate into its surroundings is apparent from the plan. The new development closely relates to its existing surroundings; the tracks lie one level below ground, and buildings on both sides form a link with the surroundings. On the eastern side, where the tracks are closest to the existing city, buildings have been constructed directly over the tracks. On the western side, where there was more space, there is a more gradual transition between ground level and the level above the trains.

The concourse of Liverpool Street Station lies at Level -1 and is directly < Aerial view connected with street level. It has high of the Liverpool Street Station spatial quality and facilitates changeover redevelopment between main line and underground. [SOM]

Despite the fact that Liverpool Street is a large terminus station, the development plan is dominated by the buildings [Glancey, 1988]. Offices do dominate the area, but the social value of the railway station has been taken into account and it presents its own face to the existing district. The station provides an important interchange between main line and underground. Much attention has been paid to public spaces; it is remarkable that a large new square in the City of London is completely free of car traffic.

The fact that the Broadgate development consists almost entirely of offices means that there is little life on the streets. Public areas are kept free of vandalism and rubbish by a brigade of 50 security and cleaning staff [Spring, 1988]. Another effect of developments on this scale is that it is difficult to create coherence. One exception to this is the Exchange House over the ends of the platforms and the tracks. The structure indicates that something is hap- pening below it, and in this way the overhead building makes contact with the tracks, forming a landmark for the area. Art is an important part of the public space. Rosehaugh Stanhope demonstrated that, as a developer, they take initiatives concerning the requirements of tenants, research and planning, structural technology and art.

4.5.3 Multiple and intensive use of space Sources differ concerning the amount of land surface and building in Broadgate. Accord- ing to the developer, the land surface is 11.7 hectares, with 325 000 m2 of net floor area on it [Rosehaugh Stanhope, 1988]. Other sources quote higher floor areas. The highest is 450 000 m2 gross floor area. These differences might be due to inaccuracy, but they may

70 Reference projects

also be the result of a difference in measurement. If we assume that the net floor area of the individual buildings is correct, the total gross floor area of the project is approximately 370 000 m2. The floor space index of the project would then be 3.16. There are no clear data on the division of floor area between the different functions. The project does not include dwellings, so the only estimate that has to be made is the ratio of offices to other functions. It is estimated that 30 000 m2 of floor area is in use for other functions. There are no regulations on the maximum depth of offices, nor on the entrance of daylight. As a result, it is possible to achieve a very high FSI.

Intensive and < Function Floor area [m2] multiple use of Offices 340 000 space in the Dwellings – Broadgate project Other 30 000 Total floor area 370 000 Land surface 117 000 Floor space index 3.16

4.5.4 Structures

The Exchange < Three different types of structure have been House spans the used to build over the tracks: tracks over 80 m • The offices along Bishopsgate, on the south- in Broadgate and forms a landmark eastern side of the project, are built over the [Davies] platform area. The columns are on the platforms, where they take up a lot of space. The buildings use the structural grid imposed by the distance between the platforms. • The Exchange House crosses a bundle of tracks in one span of 80 m. The main reason for using an arch structure is that the tracks did not allow for a structural grid. • The foundations for the artificial ground level, which partly lies under the Exchange House, have been placed between the tracks. This one-storey structure is independent of the Exchange House. When modifications to the tracks below become necessary, it will be possible to remove the artificial ground level without demolishing the Exchange House above.

Steel was used for the structures, mainly to reduce building time but also because steel is lighter than concrete and because steel frame structures are part of local construction tradition. The influence of American contractors in the Broadgate project was also a factor [Reina, 1988].

4.5.5 Flexibility Market research by the developer in the mid-1980s showed that there was a demand for offices that could be easily rearranged. The offices that were constructed have large floor spans and large lobbies. Before Broadgate, 75% of the office space in the City of London was built before the advent of the personal computer [Rabenek, 1990]. These older buildings were not equipped for the large-scale data transfer required by financial institutions [Hannay, 1991]. The new buildings are flexible in their internal arrangements.

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The development of Broadgate was very well planned, meeting the changing demands of the tenants. The fourteen buildings are completely independent, structurally, mechanically and as concerns their safety and air-conditioning systems [Rosehaugh Stanhope, 1988]. Selling individual buildings is therefore easier, which gives extra flexibility.

There is little flexibility in the layout of the tracks under the buildings of Bishopsgate, as columns have been built on the platforms. Changing the railway system under these buildings will be impossible. The situation is different for the other tracks. The Exchange House is built over the tracks, so modifying tracks and switches will be less of a problem here. It would be possible to demolish the artificial ground level under the building to enable such changes.

4.6 London: King’s Cross Railway Lands

King’s Cross and St Pancras Stations lie on the north side of the centre of London. This area is much closer to the centre of London than the Isle of Dogs, where the Docklands project (Canary Wharf) was carried out [Hall, 1987].

4.6.1 Origin When the London office market underwent the ‘Big Bang’ that made Broadgate possible, plans were also developed for the King’s Cross Railway Lands. The fact that these stations would be serving high-speed trains gave greater potential to the area. The intention was to run high-speed tracks and an associated station crosswise under the The King’s Cross existing stations of King’s Cross and St Pancras. Travel time between London and the Railway Lands Channel Tunnel would be reduced from 70 to 35 minutes and travel time to Paris to [Davies] 2 hours and 20 minutes [Bertolini & Spit, 1998]. Scotland would be connected to < < London with a direct interchange to Paris. Because of the integration of the high- Model of speed train, there was much involvement by government parties. Central government, Norman Foster’s Masterplan for local government, British Rail and private developers combined forces in the London the King’s Cross Regeneration Consortium, which later became the King’s Cross Partnership. British Rail Railway Lands owns the land [Powley & Brandolini, 1988]. [Foster] <

72 Reference projects

We shall describe Norman Foster’s winning Masterplan design below. The plans were never implemented, as the London office market collapsed, but they were developed far enough for us to draw a number of conclusions for this study.

4.6.2 Urban context The challenge of the project was to connect the city districts around the stations, which formed a ‘black hole’ in the fabric of this part of London [Grey, 1993]. The tracks for the high-speed train were to run below ground and connect with the underground. Because King’s Cross Station and St Pancras Station lie at an angle, the high-speed terminal was to be triangular, located between these two stations (see figure). The façade of King’s Cross, currently defaced by a frontal extension, was to be restored.

The buildings on the edges of the plan area would have had seven to eight floors [Grey, 1993], with two 44-floor buildings on the northern side of the area [Bertolini & Spit]. These high-rise buildings were to be a symbol, marking the project from a distance. They were placed at the end of the project area to prevent them interfering with the ‘London views’, ten views from St Paul’s Cathedral of hills outside London [interview, John Hirst].

As far as integration of the project is concerned, one important difference between the two stations is that the tracks lie at different levels. The tracks of St Pancras Station lie at Level +1, while those of King’s Cross are at ground level. The tracks from St Pancras go over the Regents Canal, which used to carry goods that had arrived by train into the centre of London. The tracks at King’s Cross pass through a tunnel under the Canal. The Masterplan reflects this situation. Buildings were planned above the tracks, with a park in the centre of the project. The existing urban fabric would have merged into that of the new scheme.

Intensive and < Function Floor area [m2] multiple use of Offices 600 000 space in the Dwellings 151 000 King’s Cross Other 73 000 redevelopment Total floor area 824 000 Land surface 540 000 plans Floor space index 1.53

4.6.3 Multiple and intensive use of space

St Pancras < As in the case of Broadgate, it is difficult to Station is a measure multiple and intensive use of space landmark of due to differences in figures from different the King’s Cross Railway Lands sources. One source gives a surface of 125 acres (50.7 hectares) [Architectural Mono- graphs, 1992], whereas another quotes 54 hectares [Quantrill, 1999]. Bertolini and Spit even gave a surface of 58.7 hectares [Bertolini & Spit, 1998]. On the basis of the different sources, the project would probably have resulted in a surface of 54 hectares. The quantity of property to be developed fluctuated during the planning process. In the table below, we have used Foster’s Masterplan as the reference for the amount of property that could have been built. The table lists the floor areas of the different functions [Tilman, 1991 & Rivolta, 1990].

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The area is a major public transport node. It was estimated that private transport would only account for 6% of total transport in the area [Quantrill, 1999]. Each flat was assigned 1.2 parking spaces, and the amount of parking places per square metre of office space would be well below normal standards. The new plans provide for one parking place per 1 000 to 15 000 square metres of office space [Argent St George, 2001].

4.6.4 Structures Because the Masterplan was not implemented, there are no concrete plans for the structures of the buildings above the tracks. Indications are found on some of the available drawings. How- ever, because parties working on the project at that time still hope to work on a new project, most data is not available publicly. The available drawings show no provisions for disturbance to the railway infrastructure. Most of the useful floor area for the buildings is almost directly above the tunnel, which fully encloses the tracks. Because railway traffic is divided between two stations, the span over the bundle of tracks is limited, unlike the 80 m of the Exchange House in Broadgate, rendering building over the tracks easier.

4.6.5 Flexibility Flexibility of the buildings appears to have been provided for. Some of the columns supporting the building have their foundations in the tunnel. There are no large spans, so changes and extensions to the buildings would be possible without much interference to railway traffic. A large part of the area is free of tracks, so buildings could be built beside them, such as the high rise structures. No further data on flexibility is available, as the project has not been implemented. The tracks have limited flexibility. They are fully enclosed in a tunnel structure that also accommodates columns for the buildings above. Increasing the number of tracks would require construction of a new tunnel below the existing one.

4.6.6 Recent plans Construction of a line for the high-speed train is now under way – the Channel Tunnel Rail Link will stop at St Pancras Station. As a result, new plans are being drawn up to develop the area [Argent St George, 2001]. This also means that a study of earlier plans is of interest.

4.7 Paris: Seine Rive Gauche

Paris has two terminus stations in the south-eastern part of its central area, one either side of the Seine: the Gare de Lyon on the right bank and the Gare d’Austerlitz on the left bank. The Gare d’Austerlitz and its surroundings are under development and will become a new < The area near district within the Boulevard Périphérique, the the Gare d’Austerlitz Paris orbital motorway. This project has involved during the building a second station, Bibliothèque François first stages of Mitterrand, which is in the process of being com- the Seine Rive pletely covered by buildings. A metro station has Gauche project also been built beneath perpendicular to that railway station.

74 <

Development plans 4.7.1 Origin for the railway The first plans to redevelop the area around the Gare d’Austerlitz date from 1987. Integrat- lands of the Gare ing the high-speed train into Paris also plays a role in the plans for this 19th century railway d’Austerlitz: Seine Rive Gauche terminus. A large part of the station was taken out of service to make the project possible, [SEMAPA] and the tracks that remain in service will be covered over by buildings.

The first step in the process was a design competition for a new national library. A Zone d’Aménagement Concerté (ZAC, designated development area) was then set up [Vliet & Kreukels, 2001]. The ZAC determines the functions to be provided in the area, the density, the heights of the buildings, etc. The Société d’Économie Mixte d’Aménagement de Paris (SEMAPA) was established to develop the area. The government (national government, the city of Paris and railway companies) owns over 97% of the company. The SEMAPA organises the infrastructure, parcels out the area and sells the sites by auction. Developers can submit a design with specifications concerning the division of functions and the heights of the buildings and add a bid for the right to build on the land. This also applies when the land lies above the railway infrastructure [interview, Theo Soeters]. The SEMAPA appoints a developer on the basis of a set of criteria.

4.7.2 Urban context The Rive Gauche (left bank) project is divided into five parts, each with its own urban designer. Along the Seine, there are three sections delimited by bridges: Austerlitz, Tolbiac and Massena. Seine Rive Gauche is split along its length by part four, which is the Avenue de France, located above the tracks. The fifth part is Chevaleret, which lies between the Avenue de France and the existing district. The tracks are at ground level, so there is a difference in height between the existing district and the artificial ground level of Seine Rive Gauche. The other side of the project has the Seine as its natural border.

4.7.3 Multiple and intensive use of space Sources differ as to the amount of building planned. This is partly because the project is still under development and construction. The surface of the land is 130 hectares. Of this, 26 hectares will be directly above the tracks [parisrivegauche.com, 2002 and Pousse, 1999/2000]. The sources also differ regarding the floor area planned. Accord- ing to some sources, the planned office space is 900 000 m2 [Pousse, 1999/2000 and

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Function Floor area [m2] < Intensive and Offices 750 000 multiple use of Dwellings 500 000 space in the Other 420 000 Seine Rive Total floor area 1 670 000 Gauche project Land surface 1 300 000 Floor space index 1.28

www.parisrivegauche.com, November 2001 and Vliet & Kreukels, 2001]. Other sources < The Bibliothèque give a figure of 750 000 m2 [SEMAPA, 199? Nationale François Mitterrand is the and parisrivegauche.com, July 2002]. Because landmark of the project organisation’s data on the internet the Seine Rive is the most recent, we shall assume 750 000 Gauche project m2 of offices. The floor area of other functions is also taken from this internet source.

The project makes multiple use of space, accommodating a large number of public functions. These include the National Library (Bibliothèque Nationale François Mitterrand) and a university building. The fact that the project includes so many public functions indicates the degree of government involvement. The offices lie close to the stations and to the Avenue de France, and hence close to and above the infrastructure. Flats are located along the Seine, creating an excellent view and placing them at a distance from the infrastructure. Apart from the Champs Elysées, Seine Rive Gauche is the only district in Paris where the number of parking places is limited to stimulate public transport [SEMAPA, 199?].

4.7.4 Structures We shall examine over-track structures on site M7. These structures are located entirely above Bibliothèque Station and have a floor area of 50 000 m2. This is the largest private development in the area. The SEMAPA made a pre-investment to enable the construction of a building above the station. This pre-investment consists of a number of columns, which are independent of the columns that support the station and the infrastructure. They are arranged on a grid, with a span of about 15 m over the tracks, and are designed to bear the weight of eight floors. This requirement was made binding on the building’s designers, which increased the costs of the outer shell. The height of the structure needed to span the tracks is used for car parking. The columns for the station are separate from those supporting the building overhead, to prevent problems with vibration [interview, Christian Schang]. Concrete was used for the structure.

4.7.5 Flexibility There is a good level of flexibility as regards the buildings. When the building needs to be replaced, it will be possible to re-use the foundations. As there is already an artificial ground level, the railway will not be disturbed during reconstruction. However, the designer cannot increase the number of floors, or more precisely their weight. The layout of the tracks is fixed; it will not be possible to modify this once the project is finished. The sidings at the two ends of Bibliothèque Station are still open, so it is not yet clear how much flexibility there is regarding these tracks.

76 Site M7 on an artificial ground level over railway station Bibliothèque François Mitterrand

in Seine Rive

Gauche < Transfer hall < of Bibliothèque François Mitterrand between the railways (ground level) and the metro (Level -2)

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4.8 Paris: Gare Montparnasse Aerial view of the Jardin Atlantique over the Gare The Gare Montparnasse lies in south-west Paris, in the 14th Arrondissement, near the Montparnasse boundary with the 6th, close to the city centre. The station forms the terminus of the TGV Atlantique to Bordeaux. The new park above the platforms – the Jardin Atlantique – is named < < after this destination. Integrating the TGV has prompted major rebuilding of the station. The Gare Montparnasse before the Jardin 4.8.1 Origin Atlantique was As this project is not a large-scale urban redevelopment, there is no long story regarding created [SNCF] its origins. The Gare Montparnasse was built in the 19th century and rebuilt in 1965, when three large buildings were constructed around the terminus. Twenty years later, rebuilding was again required, this time to accommodate the TGV. The number of passengers was set to grow because of the TGV, and a second concourse was built above the platforms. This second concourse can be reached by car and taxi [Agence des Gares / AREP, 1998]. The existing concourse was renovated and extended for the benefit of passengers who use public transport to access the station. AREP started design work in 1986, and the station was completed in 1990.

To add quality to the station, a design competition was held for a park above it. Brun & Pena won the competition in 1987 and the Jardin Atlantique was opened in 1995 [Pousse, 1995]. It has been described as the “finest waiting room in Paris” [Heery, 1997]. The three buildings around the station were also renovated and a new fourth building was constructed over the platforms. As a result, buildings enclose the park on all four sides.

4.8.2 Urban context The Gare Montparnasse already had several buildings around it before the new park and building were constructed over the platforms. The three buildings around the terminus were constructed in the 1960s and 1970s [Centre Georges Pompidou, 1978]. Enclosing the park by four buildings has created a pleasant atmosphere. The relationship with the TGV is very direct, as there is an entrance at the side of the concourse and at the ends of the platforms. The structure for the park is one storey high and is used as a car park for 700 cars [Südmeier, 1999]. There is more car parking around the station, under the three buildings, but the total number of parking places has not been established for this research.

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Rather than being fully integrated into the surrounding city, the park is something of a hid- den treasure. In addition, the buildings around the station do not relate to their urban surroundings, as they are much higher than other buildings in the vicinity. In effect, therefore, this project was an example of multiple and intensive use of space right back in the 1960s. Despite its isolation, the park is also well used at weekends.

4.8.3 Multiple and intensive use of space Because the buildings around the station are over 30 years old, it was not possible to find exact figures for the floor area. To get an idea of the amount of floor area devoted to different functions, the dimensions of the buildings were estimated in the field. The new building has a floor surface of 40 000 m2.

The land surface, as measured from a map of the 14th Arrondissement of Paris, is about 15 hectares. The buildings have a regular form, making it relatively easy to measure them. The total floor area of the projects is estimated at about 350 000 m2. The FSI is therefore 2.3. The buildings are well divided among the different functions; three of the four contain offices and the fourth is an apartment building. The other functions are integrated into the

plinth around the station and most of these ‘other’ functions are related to the station. Intensive and < Function Floor area [m2] multiple use of Offices 224 000 space at the Gare Dwellings 75 000 Montparnasse Other 53 000 Total floor area 352 000 Land surface 151 000 Floor space index 2.33

4.8.4 Structures The new entrance < Concrete has been used for the structures to the Gare of the Gare Montparnasse. Large spans Montparnasse have been created above the platforms using pre-stressed structures. The platforms also support relatively large columns, which are needed to bear the weight of the park. On one of the platforms these columns are replaced by discs, which are required to maintain the stability of the structures along the length of the platforms.

The structures are also supported beside the tracks, and the building at the end of the platforms is supported on a number of discs. Seen from beside the tracks, the building does not look as if it has dilatation joints. There are no stabilising elements visible between the tracks, so it is assumed that such elements have been placed beside them.

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4.8.5 Flexibility The buildings above the tracks do not seem to have been designed with future changes in mind. The spans look as if they have been matched to the spacing of the tracks, so this is not a standard office grid. From the outside, it does not look as if the designer used a transfer structure such as that at Rive Gauche. It is also remarkable that there is so little space between the first floor and the overhead line of the railways. Even the windows of the first floor can be opened, which would not have been allowed in the Netherlands, as people could easily touch the electrics. There is graffiti on the cladding just above the overhead line, indicating that it can be reached too easily.

The layout of the platform tracks is fixed by the structural elements located on them. How- ever, the sidings are not covered, which maintains flexibility where it is most needed, in that changes to sidings occur more often than changes to platform layout.

4.9 Berlin: Lehrter Bahnhof

Lehrter Bahnhof lies to the north of the renovated Reichstag. From a European perspective, Lehrter Bahnhof is the meeting place for the Paris – Moscow and Rome – St Petersburg high speed lines, plus S-Bahn (urban and regional overground) and U-Bahn (underground) lines. The station is currently undergoing changes that will make it the largest cross station in Europe and the central station of Berlin. It will be used by 30 million passengers a year.

4.9.1 Origin Lehrter Bahnhof in Lehrter Bahnhof was built between 1869 and 1871, as a terminus station. It was heavily the first stages damaged during the Second World War and demolished in 1959 [Krings, 1985]. The Ger- of development man parliament’s move from Bonn to Berlin prompted development of the Reichstag and sur- [R. Quabbe] rounding area, and that includes rebuilding Lehrter Bahnhof, just across the River Spree. The < < station is not directly surrounded by urban districts, which means it can be developed freely. Artist’s impression Von Gerkan, Marg und Partner won the design competition for the station in 1993, and work of future plans for the Lehrter is now nearing completion. Deutsche Bahn is investing about € 900 million in the construction Stadtquartier of the station and its related infrastructure [Vivico, 2002]. Construction was scheduled for [Planwerk the period 1996 – 2003 [Kapitzki, 1998] and the station was opened in 2006. Innenstadt Berlin] <

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4.9.2 Urban context As mentioned above, the absence of buildings in the immediate vicinity facilitates integration of the station. Lehrter Bahnhof is a cross station, with an east-west connection at Level +1 and a north-south connection at Level -1. The tracks at Level +1 follow the curve of the River Spree. A glass roof, 430 m long, forms a landmark in the city. East of the station lies the Hum- boldthafen, which is not included in this study. The two buildings over the tracks are 46 m high and stand partly on the tunnels for the underground railway line. No further buildings

over the tracks are planned. The blocks beside the tracks are about eight storeys high. Intensive and < Function Floor area [m2] multiple use Offices 161 500 Dwellings 66 500 of space in Other 26 000 the Lehrter Total floor area 254 000 Stadtquartier Land surface 143 000 Floor space index 1.78

4.9.3 Multiple and intensive use of space

The Bügelbauten < For the purposes of calculating urban density, building is a the project borders are formed by the River landmark of the Spree, the Humboldthafen, the Invalidenstraße future Lehrter Stadtquartier [von and the continuation of the Moltkebrücke. The Gerkan, Marg und Lehrter Stadtquartier occupies a larger area, Partner] but these are considered to be the borders of the station area. The surface of the station area is 14.3 hectares.

Office blocks occupy most of the area, but dwellings make up 30% of the development plans [Stadtentwicklung Berlin, 2001]. A large number of services are planned in and near the station. Part of the over-track structure (the Bügelbauten), might be used as a hotel. The division of functions and their densities are estimated on the basis of a combination of publications [Deutsche Bahn, 2001; Vivico, 2002 and several internet sources].

4.9.4 Structures

Construction < The structure of the overhead building forms of one of two a single span over the tracks, with no col- bridge buildings umns on the platforms. The Bügelbauten span (Bügelbauten) over Lehrter Bahnhof 87 m, which makes it the over-track build- [M. Schlecker] ing with the longest span in our reference projects. There are no other buildings over the tracks in this project. Where tracks pass under ground, the ground level is kept free of buildings in the project area.

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One interesting aspect of the project was the method used to place the structure over the tracks, which involved the same technique as for a lift bridge. The two halves were connected over the tracks in just one weekend possession. This minimised over-track construction time, which in turn minimised safety risks and any impact on train services.

< Connecting the Friday 29 July 2005 bridge buildings over Lehrter Start Bahnhof [Donges] Structure tipped by 9°, hoisting gear installed

Friday 29 July 2005, 22:00 hrs Tipping starts

Saturday 30 July 2005 Intermediate stage: structure tipped by 37°

By Monday 1 August 2005, 04:00 Final position Welding of bridge elements/finishing-off

4.9.5 Flexibility The Bügelbauten do not appear to be flexible in the sense of allowing a total change. Inter- nally, the buildings are flexible, in that they can be used for different functions. They are also multifunctional, the first functions being an office and a hotel. The railway infrastructure is fixed: the tunnel cannot be widened and the tracks at Level +1 will not be modified.

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4.10 Amsterdam: Zuidas

The Amsterdam Zuidas (south axis), lies between the districts of Amsterdam-Zuid and Buiten- veldert. It connects Amsterdam’s Schiphol Airport with the north and east of the Netherlands and will also accommodate a station for high-

Starting < speed trains to France. Amsterdam Zuidas situation for the will be Amsterdam’s third high-speed station, infrastructure the other two being Amsterdam Centraal of Amsterdam Zuidas, on a dike and Schiphol. The infrastructure consists of [dRO Amsterdam] a motorway, with main line and metro lines on a dike in the middle. The Zuidas is growing into an international business district and will form Amsterdam’s second city centre. The total development of infrastructure and buildings will take over thirty years.

4.10.1 Origin In 1994, the City of Amsterdam decided that the ad-hoc development of the Zuidas had to be stopped [Dienst Ruimtelijke Ordening, 1998]. An overall plan was set up to enable the area to develop into a prime office location. Broad discussion in 1996 of a concept by public and private parties led to a Masterplan Zuidas in 1998. This resulted in an overall concept for development in the area, including an urban development plan and phasing. The Masterplan put forward three alternatives: ‘dike’, ‘deck’ and ‘dock’. The City of Amsterdam chose the dock option, which involves placing all infrastructure under ground. This both provides a level landscape at ground level and connects the adjacent districts. Central government was only willing to provide enough funding for the Dike Model, i.e. the amount required to extend the infrastructure on the existing dike. The City of Amsterdam therefore needed to finance the difference in cost between the Dike Model and the Dock Model.

The Masterplan was further developed under the supervision of Pi de Bruin, the urban designer for the Zuidas, and included in the Visie Zuidas (Zuidas concept) [Dienst Ruimtelijke Ordening, 2001]. This concept is also an intermediate product in the development of the Zuidas. Under this concept, the amount of poperty to be developed grew from 1 million m2 to 2 million m2. Offices and dwellings will now occupy equal floor area, whereas the original plan had been 3:1. Schematic overview of the Dike Model with all )

the infrastructure ) on a dike <

Schematic Property (WTC) Property (offices Property (offices overview of the Station concourse Station concourse Station concourse Property (WTC)

Dock Model with all the infrastructure < < under ground Motorway Train Metro Motorway Motorway Train Metro Motorway

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In 2001, a consortium of private investors, < Artist’s Nederlandse Spoorwegen (NS, Dutch rail- impression of the future Amsterdam ways), ABN AMRO and ING (both banks), bid Zuidas with the about € 900 million for the land under which infrastructure the railway infrastructure was to be built built over [Bosma, 2002]. Putting all the infrastruc- [dRO Amsterdam] ture under ground was their most important precondition. The plan was to sell the land to developers who could bid for the sites, as in the case of the Seine Rive Gauche project. In this instance, however, the intention was that private investors should invest in development of the infrastructure from the start. If bids were too low, the consortium would guarantee a minimum land value. If the price obtained were higher, the city and the consortium would share the profits. With the money guaranteed by private investors, Amsterdam could almost afford to pay the extra costs of putting the infrastructure underground. New plans by the City of Amsterdam focused exclusively on the Dock Model. The construction costs of the Dock Model infrastructure are € 2.74 billion.

The plans for the infrastructure in Amsterdam Zuidas evolved during 2004 and 2005. One major problem with the Dock Model was that it would take 18 years to build the infrastructure and to start building above it. This was considered too long on account of the interest lost on funds invested in the tunnels for the infrastructure. A new business case was put together that included new ideas on how to build the infrastructure [Brink- man, 2004]. The key element in the new plans for the tunnels was the idea of stacking them. Stacking would create more space for temporary zones, during a series of project stages, reducing the construction period from 18 years to 12. The new plans are presented below in brief.

To speed up construction of the infrastructure, Holland Railconsult (now Movares) developed the Multi-Storey Dock Model (Stapeldok in Dutch), in which the metro and railway tracks are stacked underground. This will speed up the construction process, reducing the duration from 18 years to 12. The extra cost will be € 235 million compared to the Dock Model. The Multi-Storey Dock will also make it possible to build one integral terminal for trains and metro and will facilitate construction of an underground car park beside the new tunnels.

Following the Holland Railconsult proposal, the City of Amsterdam developed a Multi-Storey Road model as an alternative. In this model, the six-lane A10 motorway is stacked in two layers of three lanes. The construction time for this model is also twelve years, at a cost of € 140 million more than the original Dock Model. This model also creates underground space for a car park, but does not include an integrated metro and railway station.

Reference projects Cross section of < ) the Multi-Storey

Dock Model Cross section of < < Property (WTC) Property (offices) Property (WTC) Station concourse Property (offices Station concourse Station concourse the Multi-Storey P P Transfer hall Road Model

Motorway Train Parking Motorway Motor- Train Parking Metro Motor- way way Metro

Currently, central government and the City of Amsterdam have obtained sufficient funding to finance the public element of a public-private partnership for the Multi-Storey Road Model. The consortium’s € 900 million bid was annulled and private parties are now being selected by a public procedure to join this new public-private partnership. Central government requires that private parties have a major interest in the partnership, which should start in the second half of 2006.

4.10.2 Urban context The Zuidas will connect the districts of Amsterdam South, designed by Berlage, and Buiten- veldert, designed by Van Eesteren. There are two north-south routes for cars in the area, the Parnassusweg and the Beethovenstraat. Between these routes lies the central north-south axis of the plan, the Minerva-axis. This axis starts at the Amsterdam Hilton hotel and ends in the Zuidas.

Urban context of < The public transport node is situated in the Amsterdam Zuidas heart of the Zuidas, forming an interchange (the purple blocks between different forms of public transport. are located above the station) This station will be a starting point for jour- [dRO Amsterdam] neys towards France, England and Germany, and will be used for intercity and regional trains. In addition, a number of metro lines come together in the new Zuidas Station, running towards Amstelveen and the centre, southeast and north of Amsterdam. The new north/south metro line, which is under construction, will end in the Zuidas. There will also be a bus station.

4.10.3 Multiple and intensive use of space The high densities planned for the Zuidas must not be achieved at the expense of liveability. To ensure quality of life, the urban project consists of three layers. The first is the plinth. This is 10 m high and contains shops and leisure facilities. The second layer, which extends up to the 30 m level, accommodates offices and dwellings. Above the second layer there will be high rise buildings with a maximum height of 100 m. The central zone of the project area is

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Function Floor area [m2] < Intensive and Offices 1 007 000 multiple use Dwellings 982 000 of space in Other 263 000 Amsterdam Total floor area 2 252 000 Zuidas Land surface 1 720 000 Floor space index 1.31

constructed entirely on railway tunnels. Parks and sports fields are located at the borders < Cross section of of the area. The Zuidas has a land surface of multi-functional buildings above about 2 300 m by 750 m. This area will con- new tunnels in 2 tain over 2 million m of buildings, with equal areas of offices and dwellings. Much of the office Amsterdam Zuidas accommodation is already under construction and the offices are located relatively close to [dRO Amsterdam] the station. The new dwellings will be built somewhat further from the station. Once the infrastructure has been moved under ground, 1 million of the 2 million square metres of development will be placed above the infrastructure. The floor space index differs considerably within the project area. While the FSI for some sites is in excess of 10, the FSI for the project area as a whole is about 1.3.

4.10.4 Structures In the Dock variants, the infrastructure will be put underground in a tunnel. This tunnel will have to allow for the construction of buildings up to 100 m high above. It will have a grid system of 21.60 m, which is three times the standard office grid of 7.20 m. The latest plans consider only 100 metre high buildings above the parking garages between the metro and train tunnels. These plans also include stacking both metro tunnels. The structures of the buildings above the tunnels will have a span of 21.60 m, which is not very large compared to the buildings over Liverpool Street Station and Lehrter Bahnhof. They will also have a convenient grid, unlike the building over the Gare Montparnasse. The structures of the buildings have not yet been designed, but it seems logical to use steel for the 21.60 m span.

4.10.5 Flexibility Some flexibility for the buildings is provided by making the ceilings somewhat higher, so they can be used for both offices and flats [Building Business, 2002]. This creates a sort of urban flexibility. When offices are empty, the floor space can be used for flats. Building flats that can be converted into offices is more difficult, as flats have more single owners who would have to move and the building would have to include the larger number of lifts needed for the future offices, which is a substantial loss of available square metres.

Because the tracks run through the tunnel, there is no flexibility in their layout. Flexibility for the infrastructure will have to be achieved outside the Zuidas. Nor will there be any flexibility to extend the A10 ring road, which will also run under ground. This is partly because the tunnels for the north and south roads will be constructed close to the existing buildings. In the first stage, the possibility of constructing only two railway tunnels is under consideration. If this approach is adopted, it would be possible to build the third tunnel later, making it possible to respond to a growth in rail traffic through the Zuidas.

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4.11 Facts on multiple and intensive use of space

For future projects, it will be useful to have an idea of the opportunities that a location offers in terms of the density and division of functions. The reference projects have been compared to gain an insight into these factors. This analysis will look for the means and trends in density and division of functions.

Land area and < Project Land area Offices Dwellings Other Total FSI floor area Broadgate 117 000 340 000 0 30 000 370 000 3.16 assigned to Montparnasse 151 000 224 000 75 000 53 500 352 500 2.33 different functions King’s Cross Railway Lands 540 000 600 000 151 000 73 000 824 000 1.53 in the reference Lehrter Bahnhof 143 000 161 500 66 500 26 000 254 000 1.78 projects Rive Gauche 1 300 000 750 000 500 000 420 000 1 670 000 1.28 Zuidas 1 720 000 1 007 000 982 000 263 000 2 252 000 1.31

4.11.1 Density: intensive use of space The graph below plots the land surface of the project area against the floor area of the buildings. A trend line has been drawn through these points, and the line can be described as a linear function (y = ax + b).

Density of railway station area < 2 500 000 Land surface Zuidas ] versus floor 2 2 000 000 area realised y = 1.33x Seine Rive Gauche 1 500 000

1 000 000 King's Cross Railway Lands Broadgate 500 000 Total gross floor area [m Montparnasse Lehrter Bahnhof 0 0 400 000 800 000 1 200 000 1 600 000 2 000 000

Land surface [m2]

The floor space index is the derivative of the trend line and is about 1.33. The trend line goes through the origin, because when the area is very small, very few buildings can be developed. An FSI of 1.33 means that it is possible to develop approximately 13 300 m2 of floor area on one hectare of station area. However, the FSI only applies if the area is not too small. If the entire site is only one hectare, the amount of space developed on it can easily be larger than 13 300 m2.

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Density of railway station area 3.50 Broadgate < Land surface 3.00 versus floor 2.50 space index Montparnasse 2.00 y = 50x-0.25 1.50 Lehrter Bahnhof King's Cross Railway Lands Zuidas

Floor space index Seine Rive Gauche 1.00

0.50

0 0 400 000 800 000 1 200 000 1 600 000 2 000 000

Land surface [m2]

It is logical that when an area is smaller, the FSI can be relatively higher, because there is less loss of land area to infrastructure and public space. To estimate the densities for smaller areas, the surface of the area and the FSI achieved are compared. The comparison shows that the FSI can be higher when the area is smaller. Using the trend line, the following for- mula for the FSI has been found:

It is of course impossible to specify a standard FSI, as the density required in the station area largely depends on local requirements and the local property market. However, the FSI can give an idea at an early stage of the feasibility in terms of volume and costs, and provide a starting point when local requirements and market figures are not yet known.

4.11.2 Mixing of functions: multiple use of space It is advisable to develop a mix of functions in inner-city station areas. The ratio between offices and dwellings often changes to make a project feasible, mainly because of the higher yields on offices. The divisions between the functions have been compared using the figures from the reference projects. The ‘other’ category comprises shops, leisure facilities and meeting facilities. Parking facilities and public space are not calculated, because they do not count for the floor space index.

Division 1 200 000 Offices Dwellings < Relationship Other 1 000 000 between the floor areas of functions

800 000 in the reference projects

600 000

400 000

200 000

0 Broadgate Montparnasse King's Cross Lehrter Bahnhof Rive Gauche Zuidas Railway Lands Project

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The size of the projects has also increased over time. When inner-city projects get larger, it becomes even more important to mix functions, to ensure a lively city district. When only offices are developed, a large part of the inner city is deserted outside office hours. Mixing functions also has benefits for the risk and return ratio of the project, because the risks are better spread. To gain an insight into how the mix of functions in station areas has changed over time, the graph below plots projects along a time scale. Classifying the projects in chron- ological order shows that there is an increasing tendency to mix offices and dwellings.

Change in function over time < 100% Relationship Broadgate Offices Apartments 90% between the floor Other areas of functions 80% King’s Cross in the reference 70% Montparnasse Lehrter Bahnhof projects, in order of realisation e 60% Zuidas 50% Rive Gauche

Percentag 40%

30%

20%

10%

0% 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 Project

4.12 Similarities between the reference projects

Projects involving multiple use of space in station areas are carried out for a variety of reasons, and these are reflected in the projects themselves. The basic motivation is to optimise the use of inner-city space, but incorporating high-speed trains plays an important role, as do certain local conditions. This section discusses the similarities between the reference projects.

4.12.1 Use of space Lack of building space and the need for stations to be readily accessible are major reasons for investing in station areas. The potential for high rents justifies higher investments. In the reference projects, redeveloping the station area was used as an opportunity to add a large number of quality buildings to the area. The first space to be filled is any unused space close to the railway infrastructure. Examples include the plans for the King’s Cross Railway Lands, Lehrter Bahnhof and Zuidas. The next source of land is making more efficient use of railway yards and sidings, and partly moving them outside the city. Broadgate and Seine Rive Gauche are examples of this option. Finally, new space can be created by constructing an artificial ground level above the tracks and hence using the same land twice, as in the Gare Montparnasse.

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4.12.2 The high-speed network The need to integrate high-speed trains is an important reason for cities to develop their stations and the areas around them. In the case of King’s Cross, Lehrter Bahnhof and the Zuidas this includes building a new station, whereas the Gare Montparnasse and Rive Gauche projects involved major changes to existing stations. The new station area must be a city landmark and an international gateway to the city. Local authorities can benefit from an increase in property prices in the surrounding areas and the effect on the local economy. Broadgate is the only reference project without a high-speed rail link.

4.12.3 Local context and developments In addition to the pivotal position of the reference projects in their respective national railway networks, local developments play an important role in their success. The decision making processes regarding high-speed lines and stations take much longer than do local developments. Once the route of the high-speed line is known, local development can proceed faster. At Rive Gauche, the National Library has made a major contribution to the success of the project. Comparable factors dominate Lehrter Bahnhof (restoration of the Reichstag) and the Zuidas (headquarters of ABN-AMRO and ING). These factors ensure that the first phase of the project is successful, which is crucial for the project as a whole. A successful first phase also ensured the success of the succeeding phases at Broadgate [interview, Richard Jones].

4.12.4 Urban density The previous section’s comparison between use of space in the various projects indicates that they are all of comparable density. The average FSI is 1.33, which equates to 13 300 m2 of floor space per hectare of station area. The FSI of smaller projects is higher, as less land is ‘lost’ to infrastructure and public space. The FSI can be used at an early stage of a new project to estimate the area that can be developed. Obviously, the space developed must fit the local context.

4.12.5 Mix of functions Comparison of the projects reveals the mix of functions to be an important factor. Offices will not be the only function provided, especially in large-scale inner-city projects. In recent years, the percentage of space devoted to dwellings has increased.

Apartment buildings are included to enhance the liveability of the area and to spread utilisation over the full 24 hours. They also reduce the financial development risk. The spread between different functions may differ for smaller projects. Here again, local conditions may be decisive in determining the ratio of dwellings to offices. The division of functions can be used at an early stage to determine the feasibility of the project. During the project, having a mixture of functions may make it possible to follow market developments by creating dwellings and offices whenever the market is ready to pick them up.

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4.13 Differences between the reference projects

Analysis of the projects in the earlier sections of this chapter has also highlighted a number of differences. There are differences as regards the period of development, the rents, the relationship between public and private parties and the structure.

4.13.1 Period of development The reference projects took place at different periods. In terms of drawing up plans, London was the leader. As early as the mid-seventies, there were plans to build over the tracks of Liverpool Street Station, although work only started in 1985. Plans were then made for the King’s Cross Railway Lands. As a result of changes in the market, that project never got off the ground. The plans for the King’s Cross Railway Lands were also linked with the high- speed train. Development of projects in London peaked towards the end of the 1980s.

1980 1985 1990 1995 2000 2005 Periods of design < Broadgate and construction King's Cross Railway Lands of the reference projects t Gare Montparnasse ec

oj Rive Gauche Pr

Lehrter Bahnhof

Amsterdam Zuidas Design phase Construction phase

France was next. The geographically strategic position of Lille was used to develop an urban area around a new high-speed station. Integrating high-speed trains into Paris sparked inner-city station redevelopments in the early 1990s. Germany and the Netherlands followed in the second half of the 1990s. Integration of the high-speed train is well under way, but Lehrter Bahnhof is the only example of large-scale station development. The chart above shows the development and construction periods, but can only give a rough idea, as it is difficult to define the precise start and finish dates of such projects.

4.13.2 Rents Station areas are usually good locations for developing buildings because of their accessibility and their close relationship with the city centre. Rents in the reference projects differ. The graph below compares rents both between projects and between the project and the highest rents elsewhere in the same city [Jones Lang LaSalle, 2002]. In most cases the project is well located, but not all occupy the prime location in their respective cities. The estimates of the rents are partly based on confidential figures.

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Rent in 2002 1 600 1 408 Maximum office 1 350 < 1 400 rents in cities, 1 200 and rents within

/yr] 1 000 reference projects 2 800 800 732 [Jones Lang € /m [ 0 500 50 LaSalle, 2002]. 600 4 4

Rent 7 0 37 37 33 400 30

200

0 s e e .) ax Cros Zuidas Broadgate King's Paris (max.) Rive Gauch Berlin (max.) London (max.) Lehrter Bahnhof Amsterdam (m Gare Montparnass Cities and projects

There are differences between the cities, but it is interesting to note that only Broadgate and the Zuidas are in prime locations. It is also interesting that rents in the Zuidas are not far behind the top rents in other countries, and are even higher than the maximum rent in Berlin. Rents in London are much higher than in other cities, which explains why station development projects were undertaken so much earlier in London than elsewhere.

4.13.3 Relationships between public and private bodies The government plays an important role in these projects. How government gets involved will affect the way the project is run and the speed at which initiatives come about. The role of the government differs significantly between countries.

In London, the government follows market forces. The initiative lies with private parties [Vliet & Kreukels, 2001] and the results demonstrate their role. British Rail, now Network Rail, is the owner of the land; they sell land and leave development up to the private parties. British Rail is also involved in the new plans for the King’s Cross Railway Lands, as owner of the land, but again is leaving the development to private parties [Argent St. George, 2001].

In France, the situation is the opposite of that in England, in that the government stimulates the projects. In the case of Seine Rive Gauche, the government is developing the area and dividing it into sites. Private parties only develop the land they buy. The government also played a role by building the National Library. This was one of the first buildings and gave the area its initial impetus.

In Germany and the Netherlands, the government regulates the project, but restricts its investment to the infrastructure. Development of the station areas has yet to start. In Ger- many, Deutsche Bahn co-operates with local authorities to sell their land and get the project started. In certain Dutch projects, the government expects to be able to partially recoup the costs of developing the station area from property development.

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4.13.4 Urban design There are two different forms of intensive use of space in the reference projects. In Broadgate and Rive Gauche, building height is limited to protect city views, and land is used intensively. In the Zuidas, intensification takes the form of high rise buildings in the centre of the area and large public spaces at the edges. Rive Gauche and the Zuidas have the same density, but with different urban concepts. This shows that even if the same floor space index is imposed, it is possible to achieve different urban concepts.

Station area development projects incorporate a range of functions. How they do this differs. Private enterprise initiated the projects in London, and the results are largely mono-functional office developments. The original King’s Cross plans included only a small number of dwellings, but the new plans for this area pay more attention to mixing functions. Government input to the process in France has led to the inclusion of a large number of public functions. Apart from these public functions, offices and dwellings both account for a large percentage. The spread of functions in Germany is not quite clear, but given the involvement of the government these projects are unlikely to be purely mono-functional. The 30% housing in the Lehrter Stadtquartier is one example. In the Netherlands, the government will impose a mix of functions, to create a lively inner-city space.

4.13.5 Structures and flexibility The physical structures of the projects differ, in both type and material. The range of solutions adopted could also be used for other new projects. This topic will be discussed further in Chapter 8. Flexibility also differs, but is generally limited. In Broadgate, optimal flexibility for the tracks was achieved by building the Exchange House over the tracks in a single span. In Rive Gauche, flexibility of the tracks is limited in favour of the buildings above. Because of their complexity and the need to allow for modifications, the sidings remain uncovered in most cases. Chapter 5 will look at flexibility in more detail.

4.14 Specific aspects in the Netherlands

Station area development in the Netherlands has to take account of certain differences between the Dutch situation and that obtaining in other countries. This section will discuss some of these differences.

4.14.1 Local versus national lack of space The reference projects, especially those in London and Paris, came about because of a lack of inner-city building space. In the Netherlands there is also a lack of inner-city building space, but a general lack of space at a national level plays a role. In particular, saving green space around the cities is more important than in neighbouring countries. The reference projects outside the Netherlands were carried out not because of any governmental policy on multiple use of space, but rather to create more space in the inner cities.

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4.14.2 Typology of stations Except for Lehrter Bahnhof, all the foreign reference projects are terminus stations. The Dutch ‘key projects’ on a similar scale are all through stations, except for Den Haag Centraal. The vertical position of the tracks also differs. Dutch through stations have tracks at Level +1. Reducing the barrier created by these Level +1 tracks is much more difficult than reducing the barrier created by tracks at ground level or subsurface, as in the cases of Rive Gauche, Gare Montparnasse and King’s Cross. The position of the through station in the city makes integrating such projects even more difficult, as the barrier effect may be greater when development is concentrated in the old city centre. This makes the difference between the two sides of the station even more marked. In the Zuidas, plans focus on bringing the infrastructure underground. This makes integration much easier, as the Broadgate project shows.

4.14.3 Density and mixing of functions The floor space index presented in 4.10 can be applied to the Dutch context. The FSI must reflect local requirements and property markets. While it can be higher on smaller sites, Dutch cities are not planned as densely as London or Paris. The FSI can be used at an early stage of the project to get an idea of whether it is feasible. In some cases, as much as half the area is devoted to dwellings. About 10% to 15% of the floor area can be used for other functions.

4.14.4 Benefits at project level The benefits of property development in the Netherlands will be substantially lower than in London or Paris. The Zuidas is an exception, as rents here are far higher than in other locations. If such developments are to take place in the Netherlands despite lower land values, the following scenarios could be considered:

• Prohibit building outside cities. This might raise the value of land in cities to a point at which building over tracks becomes more interesting financially and the extra investment is affordable. • Calculate the social benefits into the project, if it is socially desirable that station areas be developed. In this scenario, inner-city redevelopment would be subsidised on account of the green area it preserves and the public transport it stimulates by creating offices and housing close to stations. • Not build over the tracks at first, but so design initial developments that they can be covered in the future, when this becomes financially feasible. • Treat the whole station area as one project, in which the more expensive buildings over the tracks are subsidised by the buildings that can be developed at lower cost in the area. It might also be possible to levy an area tax, as owners will profit from a rise in the value of existing buildings.

4.14.5 Public-private partnerships The complexity of developing a station area and the range of disciplines involved make it logical that public and private bodies cooperate. Every type of expertise is needed to make such projects a success. The government can be a catalyst by initiating and facilitating the

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process. This does not necessarily mean that government has to make large investments at the start. When the plans become more concrete, the government should be clear about the amount of money it is willing to invest on account of the social value of developing such projects. This money can be used as a pre-investment to get the project off to a good start. Private parties will be more willing to invest in the location if the government is committed. The Zuidas project has been set up in this manner.

4.14.6 Transport of hazardous goods Because the Dutch railway network includes through stations in inner cities, it is common for hazardous goods to pass through densely populated areas. Regardless of any redevelopment, this is already a problem. The reference projects do not encounter this problem, as hazardous goods are not transported to inner-city terminus stations. Dutch projects must plan for incidents involving chloride and LPG. It may not even be possible to develop an acceptable covering structure for the tracks if LPG is transported underneath in an enclosed space. The transport of hazardous goods will raise the costs of Dutch projects.

4.15 Conclusion

Building over tracks is an international phenomenon. The first example was in New York, 100 years ago. An overview of European examples shows that many buildings have already been constructed over railway infrastructure. Such structures have been built over different types of station and at different vertical positions relative to the tracks. The available literature indicated that as yet there has been no in-depth study on multiple and intensive use of space focusing on projects that include over-track structures.

Only a small number of projects in Western Europe satisfied the criteria for further study within the present research. Comparison of the six reference projects selected on the basis of these criteria allows us to draw conclusions regarding their similarities and differences. Similarities include: • Comparable use of space (beside the tracks, on re-arranged railway land and over the tracks, in that order). • Comparable urban density in terms of the floor space index. • A general trend towards a better mixture of functions, even in larger projects.

Furthermore, most projects are related to the process of integrating high-speed trains, and in most cases are the result of the planning process for high-speed. However, the main success factors are not the high-speed train itself, but local context and return on investment. A successful first phase is particularly important.

Most differences are differences between countries, rather than within the same country. Chronology is one difference, with buildings over railway infrastructure starting as follows: • London: second half of the 1980s. • Paris: 1990s. • Germany and the Netherlands: second half of the 1990s.

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This difference is mainly due to the price per square metre of buildings, the privatisation of rail and the extent to which public and private parties participate: • London: private. • France: public. • Germany and the Netherlands: the developments take longer because private and public parties need time to combine forces and to divide tasks and responsibilities.

Another cause is a difference in rent level. When rents are higher, it is easier to build over tracks: • London: office rents are very high, so private parties can develop these projects on their own. • Paris: rents are lower, but high enough for public bodies to run the development themselves. • Germany and the Netherlands: rents are substantially lower and public and private parties need to join forces in partnerships, which leads to long and complex processes to make the project feasible.

There are also differences in urban design. Many inner-city railway areas do not allow high-rise buildings because of historic city views. In these projects, intensive use of space can only be achieved by occupying a large percentage of the land surface. In the Amsterdam Zuidas, high-rise buildings are part of the project plans, enabling high local floor space indices and leaving other areas of the project relatively open for parks and sports fields. Structures also differ: in London, buildings over tracks are constructed in steel, while projects in Paris use concrete.

Apart from similarities and differences, there are some specific points regarding the Dutch situation. Lack of space in the Netherlands is not an inner-city lack of space, but a national lack of space, which means that the land value of inner-city areas is not high. Also, almost all Dutch stations are through stations, which are more difficult to build over because the tracks are more intensively used than at terminus stations such as in London and Paris. Furthermore, the transport of hazardous goods through urban areas, which is specific to the Netherlands on account of the network of through stations, raises both costs and risks, limiting the scope for building close to and over the track.

The findings of this chapter will be used as a basis for the following three chapters. Chapter 5 will discuss the quality and flexibility aspects of building over tracks, while Chapter 6 will look at such technical aspects as noise and vibration. Chapter 7 will deal with the problems of physical safety that arise, partly because of the transport of hazardous goods.

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Chapter 5 Quality and flexibility

The preceding chapters analysed reference projects involving multiple and intensive use of space in station areas. The success of these projects partly depends on their spatial quality and their ability to adapt to change. Station areas are densely built-up, and are used by large numbers of people. The spatial quality of both the station and its surroundings are important. These areas change over time, and to maintain quality, the design of the station and its surroundings must be flexible enough to adapt to changing requirements. This chapter will deal with the quality and flexibility of buildings and railway infrastructure in the context of multiple and intensive use of space. It will also take account of the relationship between quality and flexibility. The chapter will start by briefly drawing parallels between building over railways and underground construction.

5.1 A new form of underground construction?

Underground construction has developed considerably in recent years. It saves scarce inner-city land by creating new space while having a limited impact on its environment. Under- ground space is mostly used for infrastructure, parking facilities and amenities such as shopping and leisure centres. Putting infrastructure underground has the further advantage of using virtually no indirect space, as the infrastructure needs no space around it to take account of noise or safety issues. Underground shopping centres reduce walking distances, as the layers are stacked. However, it is virtually impossible to put homes and offices under ground, due to legal restrictions and the lack of daylight. It is also difficult to modify or extend underground structures to match changing requirements.

As an alternative to building new infrastructure under the existing city, one can build a new city on top of existing infrastructure. Building over railway infrastructure makes it possible to stack functions logically: buildings (which need daylight) above, and infrastructure (which does not) below. When existing infrastructure is built over, a new form of underground space

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emerges that is much cheaper than putting new infrastructure underground. However, exist- Les Halles ing infrastructure is not designed for this ‘underground’ situation. Covering a station blocks underground shopping centre, out daylight from platform areas, and this must be compensated for. The following sections Paris. Daylight is will discuss the effect that building over a station has on the spatial quality of the platform limited and it is area and of the urban surroundings. difficult to change or extend the space. 5.2 Spatial quality < < The Groene Hart Spatial quality is an important keyword in urban development. The concept is outlined in gen- Tunnel in the Netherlands. eral terms in the Fifth National Policy Document on Physical Planning of the Dutch Ministry Infrastructure of Housing, Spatial Planning and the Environment [VROM, 2000]. To discuss ‘spatial quality’ tunnels play a in the present study on building over infrastructure, we need a definition. There are, however, major role in many definitions of spatial quality. Some sources refer to the theories of Vitruvius (about underground construction. 60 BC) [Hooimeijer, 2000 & Verbart, 2004]. Vitruvius defined the (architectural) quality of a building in terms of three elements: venustas (beauty), utilitas (usefulness) and firmitas (soundness). Hooimeijer et al. use other elements: utility value, experience value and future value [Hooimeijer, 2000].

To assess the spatial quality of platforms (transport quality) that have been built over, we must work at a smaller scale. In her PhD thesis, Durmisevic focused on the quality of underground urban space as perceived by its users [Durmisevic, 2002]. This research provides a better starting point for assessing the change in spatial quality in projects involving the multiple use of space. It also proposes a number of aspects that can be taken into account. The study addresses spatial and psychological aspects, and the relationship between them. Wijk and Luten have looked at aspects of spatial quality related even more closely to the present study [Wijk & Luten, 2001]. They discuss the ergonomics of the built environment and the variables and limits governing its design, attaching considerable importance to the idea that the built environment is to be designed for everyone, and not for the average person [Luten, 2006].

As far as the assessment of spatial quality of the station area (urban quality) is concerned, we shall be analysing the principles of Lynch [Lynch, 1960]. Lynch divides the image of the city into five elements: paths, edges, districts, nodes and landmarks. We shall examine these elements as they apply to station areas.

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Although limited literature is available on this subject, the above information has been used to set up a basic framework for assessing both transport quality and urban quality.

5.3 Transport quality

Building over tracks affects the spatial quality of the railway infrastructure underneath. The use of station space can be divided into transfer and accommodation. Transfer criteria are the ease with which passengers can find their trains, the ease with which they can change trains or change to other transport modes, and the accessibility of the station. Accommoda- tion criteria describe the user’s perception of the quality of a space while inside it. Accom- modation requirements are more stringent, as people who remain within a space are more aware of their surroundings than are those who simply pass through. This section focuses on how users perceive the quality of a platform area that has been built over, as building over railway infrastructure has a substantial impact on the quality of the platform area. We will look at a number of examples and identify ways of optimising the spatial quality of platform areas.

5.3.1 Assessment parameters An interview with Ita Luten has identified four different levels of spatial quality requirement. We shall use these four levels to assess the spatial quality of platform areas with buildings overhead. The first level requirements are those related to the structure. A structure must be strong enough and stiff enough to bear the load of an overhead building. It must also be watertight. Structural requirements (1) are strict, and are laid down in legislation such as the Dutch Building Decree (Bouwbesluit). Once the structural requirements have been met, we can turn to those regarding the form (2). The proportions of the free space under the structure must be appropriate and the space must be attractive. Attractiveness is of course subjective, but for instance one should avoid very low ceilings over 450 m of platform. The basic form requirements lead on to more specific functional requirements regarding the space, the transfer requirements (3). Platform areas are used for the transfer of passengers, so enough transfer space should be available. Furthermore, the use of the platforms as transfer space gives rise to requirements regarding clarity and routing, perhaps involving the

use of signage. Finally, in many situations there will be requirements regarding the platform < Structural Strength, stiffness, stability, cohesion Four levels of requirements Water-tightness requirements regarding the spatial quality of Form Shape and size, spatial dimensions platform areas requirements Attractiveness with buildings above [Based on Wijk & Luten, 2001] Transfer Transfer space requirements Routing and signage

Accommodation Comfort/building physics requirements Lighting, colour, acoustics, temperature, air quality

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area as an accommodation space (4). When passengers are waiting on the platforms they will be more aware of their environment. It is important to make the accommodation pleasant enough by controlling the temperature, the lighting, the acoustics and the air quality (e.g. humidity and odours). The ergonomics described in Wijk & Luten have a broader context than indicated by these four levels. Furthermore, the different aspects influence one another. The four levels form the architecture and they are of value in making a quick assessment of the spatial quality of real-life reference platform areas.

5.3.2 Spatial quality of reference platform areas Spatial quality can be assessed for existing projects where railway platforms have been built over. In Chapter 3, we defined four different vertical track positions in stations, and we shall use these for the assessment of reference platform areas. The positions were: underground, subsurface, ground level and elevated. The references are drawn both from the Netherlands and from abroad. Platforms have been built over in all cases other than in underground stations. For underground stations, however, the situation is comparable to that of building over the platforms of an overground station. An assessment of the platforms for all four requirement levels seperately is beyond the scope of this research. We shall, however, provide a more general overview of spatial quality, to give an impression of average spatial quality levels at present.

Underground platforms Rotterdam Blaak Station has the deepest platforms in the Netherlands, 14 m below Underground ground level. Spatial quality is created by enabling as much daylight as possible to reach the platforms at middle of the platforms [Vákár, 1993], and daylight is used to guide passengers to the sta- Rotterdam Blaak Station. Daylight tion exit. Daylight does indeed reach the centres of the platforms, through a glass roof, but guides passengers very little reaches the ends. Spatial quality deteriorates towards the platform ends because towards the exit. of insufficient daylight and artificial light. This has been done to guide the passengers [F. van Dam] to the exit. However, the finishing of the platform area compensates for this in part. < < Antwerpen- Antwerpen-Centraal was a terminus station with 12 platforms at Level +1. New underground Centraal during reconstruction. A platforms and tracks have been constructed at Levels -1 and -2, and the existing terminus large void channels station is being transformed into a through station at Level -2. The twelve platforms at Level daylight directly to +1 have been reduced to six, to create a large void for the new underground platforms Levels -1 and -2. <

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Subsurface [Buyten, 1992]. Daylight reaches the platforms at Level -2 via a glass canopy and this void, platforms at enhancing the spatial quality of the platforms. Rijswijk Station. Openings in the tunnel These two examples meet requirements at all four levels. Both the transfer quality and the deck function accommodation quality of the platforms is adequate. In addition, Blaak Station shows the as spotlights, positive effects of design on spatial quality. darkening the surrounding space. Subsurface platforms The tracks through Rijswijk have been placed under ground to upgrade the quality of the urban

< < < space [Durmisevic, 2002]. Hardly any daylight reaches the new, subsurface platforms. Worse Subsurface still, such daylight as does reach the platforms takes the form of bright ‘spotlights’ of daylight platforms at channelled through small openings, dazzling passengers and accentuating the surrounding London’s Liverpool darkness. This lacks even a guidance function. Bringing the tracks subsurface has led to a Street Station in London, with little substantial deterioration in spatial quality for passengers. However, the underground area of artificial lighting the station does have good proportions, which means that adding indirect artificial lighting and improving the wall finishing and the fittings would be sufficient to raise the spatial quality of the station to an acceptable level. Such indirect artificial lighting has recently been installed, which indeed upgraded the spatial quality. Indirect lighting can enhance the perception of space.

The redevelopment of Liverpool Street Station and its surroundings in London substantially improved the urban quality of the station area. One building, the Exchange House, has been built over the sidings and the ends of Platforms 1-10. The remaining platforms, 11-18, were built over completely, blocking out the daylight. The spatial quality of these platforms is very poor compared to that of Platforms 1-10. The platform area has limited height and poor artificial lighting. However, a white ceiling has maximised the effect of what lighting there is. Crime prevention is taken care of by placing automatic ticket barriers at the platform entrances, but this does nothing to improve the subjective perception of safety.

These two stations have been less successful in meeting quality requirements than were Rotterdam Blaak and Antwerpen-Centraal. Rijswijk meets transfer requirements by providing enough space to reach the trains, but fails to ensure sufficient accommodation quality. By contrast, the platforms of Liverpool Street Station leave little space for transfer because of the columns of the buildings overhead, but satisfy accommodation requirements to a greater extent than Rijswijk because they are better finished.

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Ground level platforms The platforms at Den Haag Centraal is covered by a bus and tram station. The concrete deck above the plat- Gare Montparnasse in Paris are forms has a small number of openings for stairs, escalators and lifts. Very little daylight reaches covered by a the platforms through these openings. Because the platforms are at ground level, daylight also park, but large reaches them horizontally from the far end, forming a disturbing type of back-lighting. This voids in the deck is made more unpleasant by the low level of artificial lighting, the two factors combining to allow daylight to penetrate produce a sharp contrast. Moreover, the finishing of the space is comparable to that of the platforms that have not been built over, whereas it should be better to compensate for the lack < < of daylight. The space is also too low, leaving little margin for improving spatial quality. The platforms at Den Haag Centraal are covered by a The ground level platforms at the Gare Montparnasse in Paris have been covered by a park. bus station. There The spatial quality of these platforms is higher than that of Den Haag Centraal; there is more is not enough headroom and larger openings, providing sufficient daylight. The openings are also larger artificial lighting than at Rijswijk Station, avoiding the ‘spotlight’ effect. However, daylight is not used to guide to counteract the unpleasant back- passengers as in Rotterdam Blaak. Where less daylight reaches the platforms, spatial qual- light effect. ity deteriorates considerably. This is partly compensated for by a simple but clean finish.

Den Haag Centraal, like Rijswijk, fails to provide an acceptable accommodation space. How- ever, as this is a terminus station that is less important, because the platforms are mainly used as transfer space. The Gare Montparnasse is also a terminus station, with platforms that mainly function as transfer space. The space is higher, however, which enhances clarity, and daylight does not enter the platforms in the form of unpleasant back-lighting.

Elevated platforms The platforms in Utrecht Centraal are covered over by the Katreinetoren (offices), the station concourse and a broad walkway. Daylight enters the platforms from the ends and partly from the sides, as the tracks are slightly above ground level (though only by two or three metres). There is back-lighting, but it is not as disturbing as in Den Haag Centraal. However, this ‘underground space’ has the same finishing as the platforms that are not built over, and lacks sufficient artificial lighting.

Much attention has been paid to the finishing of the platforms in the built-over part of Charing Cross Station in London. The built-over area has been finished differently to the uncovered platforms. As a result, spatial quality is acceptable for passengers, even though headroom

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The platforms at is limited. The level of artificial lighting is higher than at Den Haag Centraal, compensating Utrecht Centraal for the back-light from the platform ends and reducing the unpleasant contrast. In addition, are covered by a it was possible to keep the platform in the middle column-free, as the office floors are sus- concourse and walkway, but are pended from a superstructure.

poorly finished < < < The platforms of Utrecht Centraal are used as accommodation space, but do not meet accommodation requirements. The covered section of Charing Cross does a better job of The platforms at meeting accommodation requirements, even though it is primarily used as transfer space. Charing Cross Station in London are also built over 5.3.3 Similarities and differences in spatial quality Building over tracks tends to have a positive effect on the spatial quality of the station area but a negative effect on the spatial quality of the platform area. The problem is made more acute by the fact that platform areas are used more intensively than the urban space around them. The deterioration in spatial quality stems mainly from blocking out daylight without providing adequate compensation in the form of artificial light; sufficient light is required both for security and for orientation. In some cases the headroom is too low, creating a tunnel effect. This is acceptable in metro stations, which have a length of about 120 m, but main-line platforms may be up to 450 m long. When tracks are built over, it is difficult for passengers to orient themselves with respect to their surroundings and to find their way. One essential difference between Dutch stations and those of other countries is the way in which platforms are used. Most Dutch stations are through stations, where a train stops for three minutes – or even less – and then continues its journey. In those three minutes passengers must get out and new passengers must get in. If a passenger wants to take the train he must already be standing on the platform before the train enters the station. By definition, a train arriving at a terminus terminates. Passengers alighting have enough time to leave the platform and passengers joining the train have enough time to do so. At terminus stations, passengers can wait on the concourse, whereas in through stations they have to wait on the platform. As a result, the platforms of through stations are both transfer and accommodation spaces. In turn, this means that the quality of the platform area in through stations must be higher than that of terminus stations. And yet when we compare the spatial quality of built-over through platforms in the Netherlands with that of built-over platforms at terminus stations in other countries, we find that the spatial quality abroad is higher, despite there being less need. So there are important challenges for existing projects in the Netherlands – and even more so for future projects. The next section will discuss ways of enhancing spatial quality.

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5.3.4 Ways of ensuring spatial quality on platforms There are various ways of meeting spatial quality requirements on built-over platforms from a passenger perspective. These methods are related and each of them may contribute to meeting requirements at more than one of the levels of spatial quality we defined above. In this section, we shall attempt to structure them.

Optimal spatial proportions: When platforms are built over, passengers are enclosed by the buildings. To ensure that they do not feel confined, it is important to create sufficient headroom over the platforms. This is also a factor in crime prevention. The required headroom depends on the length of platform that is covered, the length of the span over the platforms and the width of the platforms. Providing sufficient headroom enables passengers to orient themselves more easily with respect to their surroundings. Once construction is finished, it will not be possible to change the ratio of width to height, i.e. it will not be possible to increase the height, so it is important to incorporate sufficient headroom into the design.

Structural solutions: The design of structures over railways can be used to optimise the spatial quality. Using slender columns, limiting the number of columns and creating large voids for daylight penetration can all help to give passengers a clear view and a sensation of well-being.

Platform layout: The platform layout must be so designed as to provide enough transfer space for passengers to reach the train. It is important to limit the number of obstacles and to site such required facilities as seating so that they do not impede the transfer function. Clear, user-friendly platform layout enhances spatial quality.

Daylight and signage as navigation tools: Daylight makes a significant contribution to the spatial quality of built-over platforms. It helps passengers to orient themselves. Daylight can be used to give passengers a notion of weather conditions and the time of day. Where possible, it should be used to guide passengers and to reduce the incidence of crime. Passengers follow light when attempting to find their way. It is therefore preferable that when passengers follow the light they reach the station exit or the concourse. Rotterdam Blaak is a good example. Artificial light and other techniques may also help passengers find their way.

Daylight and artificial light: Daylight and artificial light determine much of the accommodation quality. By definition, building over the track takes away daylight and creates an interior space. It is possible to compensate for the lost daylight by adding artificial light, but the division between the new artificial light and the daylight that still enters the space must be coordinated. Artificial light can also be used to give the station a specific character. Daylight may encourage crime if there is little of it, or when it has a blinding effect, or when it forms a disturbing back-light [Oey, 1999]. The example of Rijswijk station shows how daylight can cause a sharp contrast, intensifying the darkness, so daylight is not always positive. Artificial light cannot compete with daylight (150 lux versus 10 000 lux). Finally, a stark contrast also has an effect on railway safety, as drivers may be blinded by back-light when leaving the station or sudden darkness when entering it.

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Finishing: Like daylight and artificial light, finishing can make a major contribution to accommodation quality. Creating an interior space imposes requirements for finishings. The finishing of an interior space differs from that of an outside platform. The examples of Utrecht and Rijswijk clearly show that much accommodation quality is lost when the materials used inside are similar to those used outside. Charing Cross Station shows that high-quality finishing is an important component of spatial quality; for instance, white floors and stainless steel cladding can help to create a high quality finish. Reflective surfaces are particularly useful, as there will be less light in a covered platform area.

5.4 Urban quality

The spatial quality of station areas is generally not very high, owing to the negative external influences of railway traffic, such as noise and both visual obstruction and physical obstruction. This is less of a problem near the station, where the station building largely blocks out these influences. But where this screening effect is not present, urban quality deteriorates because of the sharp contrast between railway infrastructure and the surrounding areas. At the station, the city and the railway infrastructure support each other in defining the area as a node and a meaningful place in the urban fabric. However, the tracks interfere with their surroundings and the transition between the infrastructure and the city is often poorly designed, creating a barrier in the urban fabric. In addition, the railway occupies considerable space in the form of sidings and yards. These spaces have no added value for the city itself. Indeed, they may well create a serious barrier. Redevelopment and building over tracks can help to improve urban quality. The spatial quality of the surroundings makes a significant contribution to the creation of a pleasant, crime-free space in which to live and work. One can apply the principles proposed by Lynch [Lynch, 1960] to structure assessment of urban quality in station areas. Lynch divides city image into five elements: paths, edges, districts, nodes and landmarks. We shall discuss these elements for different redeveloped station areas.

• Paths: Paths are the channels along which the observer customarily, occasionally, or potentially moves. For some references, we shall describe such paths as central axes through the station area. • Edges: Edges are the linear elements that the observer does not use or see as paths. Edges in a station area may be the walls along the tracks, or parallel routes. • Districts: Districts are the medium-to-large sections of the city, conceived of as having two- dimensional extent, which the observer mentally enters into and which are recognisable as having some common, identifying character. The station area itself is a district. • Nodes: Nodes are points, the strategic spots in a city that an observer can enter, the intensive foci to and from which he is travelling. The station itself is of course a node. Squares and parks in a station area can also function as nodes, and will also be discussed. Nodes are accomodation spaces, whereas the paths are transfer spaces between the nodes. • Landmarks: Landmarks are another type of point reference, but in this case the observer does not enter them; they are external. In many station redevelopment projects, new buildings have a landmark function. They will be discussed below.

105 Rail Estate < These elements are the raw material of the environmental image at city scale. They must be Amsterdam patterned together to provide a satisfying form. As this study focuses on a possible assess- Zuidas, the future Minerva Axis, ment of the urban quality of a station area with buildings over the tracks, and not on the comparable with urban design itself, the following gives examples of the five critical elements. the axis of La Défense with its 5.4.1 Paths Grande Arche [dRO Amsterdam] Streets and roads function as paths and form the internal and external connections of a station area development project. They are an integral part of the urban design, determining < < the character of the new urban area. Streets and roads have a transfer function and ensure Seine Rive structure and overview. The Avenue de France of the Seine Rive Gauche project is an exam- Gauche, the Avenue de France ple of a central axis in a redevelopment area over railway infrastructure. The Minerva axis in is a structuring the Zuidas project will form the central axis from north to south. These axes are paths that axis in this connect different nodes, the public spaces. new area

Developing the station and the station area should encourage more intensive use of the railway infrastructure and ensure good integration between the station and its surroundings. These connections are transfer spaces, or paths. We shall consider the relationship between the vertical position of the tracks and the integration with urban ground level for different vertical track positions.

When platforms lie under ground level, the connection between the city and the platforms is directly via stairs, an escalator or a lift. This connection between station and city can be seen at underground and subsurface stations, such as Liverpool Street. Liverpool Street also has a connection with its surroundings at Level -1, at the beginning of the platforms. The connections around the station are at ground level, which minimises the negative impact of railway infrastructure on the urban fabric. Where tracks pass under ground, there can be a link between districts on opposite sides of the railway infrastructure. This will be the case in the Amsterdam Zuidas Dock model.

Island platforms at ground level can be reached by passing under or over the tracks. At a terminus station, it is also possible to access platforms from the end, at ground level. A subway is frequently used, as this requires passengers to climb fewer steps than does a footbridge over the tracks. A subway requires the pedestrian to descend approximately 3 m and then climb 4 m to reach the platform. A footbridge involves climbing at least 6 m from ground level

106 Introduction

Future station with platforms below ground

level, Amsterdam

Zuidas < Connection < between ground level and platforms at Level -1, Liverpool Street Station

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to get above the overhead line and then descending 5 m to reach the platform. When tracks A staircase leading are built over at ground level, pedestrians are guided over the tracks, which may result in a to the artificial ground level of lively urban space at the new artificial ground level. Seine Rive Gauche is an example of this. Rive Gauche Subways to platforms are often used because they are functionally most efficient, but they do invite crime in many cases. < < A connection When the platforms lie at Level +1, connections are made underneath at ground level. Only underneath of the platforms in individual buildings are constructed over the tracks, and each has its own connection to Charing Cross ground level beside them. There can also be direct connections to the platforms. It is difficult Station connects to create an artificial ground level over platforms at Level +1, as there are already connec- the urban districts tions under the platforms and the artificial ground level will hardly be used as it will be difficult on both sides of the infrastructure to reach. The only users will be the people occupying the new buildings. The buildings over Charing Cross, Cannon Street and Blackfriars Stations are examples where only buildings have been developed, with no artificial ground level. The Seine forms one edge of Rive Gauche clearly 5.4.2 Edges marking its Edges are the second element in the image of the city according to Lynch. Stations are usu- boundary ally redeveloped in an urban context, and in most cases the existing city will mark the edge of < < the area. In the case of the Gare Montparnasse, the edge that was originally formed by the Large buildings tracks is now formed by long, tall buildings alongside them. The Seine Rive Gauche project form the edge also has one edge along the existing city, with the River Seine forming another. Finally, the of the Gare Mont- tracks themselves are an obvious edge in many reference projects. parnasse project <

108 Introduction <

The Broadgate 5.4.3 Districts Arena, a square as The station area itself can be seen as a city district. This district must function as a whole, to a central element make the district recognisable to the user. We have already examined the urban context of in a redeveloped station area different reference projects in Chapter 4.

< < < 5.4.4 Nodes The Jardin Nodes form the public spaces of a station area. Public space is an important aspect as they Atlantique are accomodation spaces to their users. Although functions are mixed in different buildings or above the Gare on different layers, the real mix is in the public space. In terms of the quality of public space, the Montparnasse enhances spatial amount of open space is important. The Open Space Ratio (OSR) is the relationship between the quality total gross floor space and the non-built ground space [Berghauser Pont, 2002]. In this indicator, such private space as commercially occupied space (terraces) and private gardens is also considered open space, although it is not unconditionally freely accessible. Large open spaces that are not used can be as unpleasant as small open spaces that are over-crowded. In addition, the amount of open space should also have some flexibility. When buildings are added later or buildings are demolished, it may become necessary to change the amount of open space.

Squares and parks are given a luxury finish, as they are intended to please the public. If the square is kept free of car traffic and there is sufficient surveillance, pedestrians can enjoy a high level of spatial quality. The Broadgate Arena at Liverpool Street Station is one example, illustrating the extent to which it is possible to enhance the quality of a redevelopment project with well-arranged public spaces.

As an alternative to a square, it is possible to add large public accommodation spaces to a station area in the form of a park. Adding a park to a redevelopment project can vastly enhance the spatial quality and make a stay more pleasant. An interesting example of a park over railway infrastructure is the Jardin Atlantique above the Gare Montparnasse in Paris. This park is an asset to the area and passengers can use it as a waiting room before descending the stairs to their platforms. However, a brief visit to this area indicated that only a limited number of travellers actually do so. The park has substantially enhanced the quality of the existing surrounding buildings by the new view it offers. Rijswijk Station also has a park over the tracks, but unlike the Jardin Atlantique this park is just a patch of left-over space. It does not connect anything and simply awaits further development, rather than forming an accommodation space for passengers and residents.

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5.4.5 Landmarks The French The quality of the station redevelopment largely determines the quality of the whole area. National Library, a landmark of Buildings often function as a landmark. When discussing ‘landmarks’, we can divide buildings Rive Gauche into three categories: external landmarks (the effect of which extends beyond the station area), internal landmarks (buildings that are only landmarks within the area) and buildings < < that do not constitute landmarks at all. The offices over Charing Cross Station are a External landmarks determine the image of the project area well beyond the boundaries of landmark the area itself. The building over Charing Cross Station beside the Thames and the French National Library on the left bank of the Seine are good examples. High buildings as landmarks for the area were also included in Norman Foster’s (abandoned) design for the King’s Cross The Exchange Railway Lands [Bertolini & Spit, 1998]. In their relatively open context, the buildings over the House is the Lehrter Bahnhof also function as an external landmark. internal landmark of Broadgate. The There are also high-quality buildings that have a more internal landmark function, for arch refers to the infrastructure instance because they are smaller than the neighbouring buildings. Even though they do underneath. [SOM] not function as external landmarks, they do make an important contribution to urban qual- < < ity within the station area. The Exchange House over the tracks at Liverpool Street Station is an example of such a landmark. From outside the project area this building is almost The Orient Express flats above the invisible, but within the area it is striking and gives a clear reference to the railway infra- Rijswijk Station structure below. tunnel have no specific identity. <

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When a station area is redeveloped it is not possible to give all the buildings a landmark function. There will always be buildings with a ‘normal’ appearance. The buildings over and around the Gare Montparnasse are examples of buildings over railway infrastructure without a specific appearance, as are the Orient Express flats over Rijswijk Station. Liverpool Street and Seine Rive Gauche also include many buildings with no specific architectural quality, but which are nonetheless finished to a high standard.

5.5 Aspects of flexibility

Both the transport system and the urban environment must be flexible, so as to meet changing quality requirements. We shall divide discussion of flexibility into ‘transport flexibility’ and ‘urban flexibility’. For each area, we shall distinguish between four types of flexibility:

• Phase-ability: Combining building over railway infrastructure with redevelopment of the station area can lead to large projects, which may last many years. In the case of the Amsterdam Zuidas project, for instance, it will take about 15 years to build the infrastructure and another 25 years for the overhead buildings. Usage requirements and regulations may change during the planning and execution phases of such projects. The plan must be able to meet these changing requirements. When a project is properly phased, the different phases allow such changes. • Maintainability: When a project is finished, a period of short term and long term maintenance starts. Maintenance includes regular cleaning and replacement of parts of structures or parts of the railway infrastructure. Maintenance must interfere with ongoing activities – especially railway operations – as little as possible. • Changeability: When requirements regarding the use of the railway infrastructure or the buildings over and around the infrastructure change, a project must have the flexibility to change so that it meets the new requirements. These changes go further than the replacements mentioned above under ‘maintainability’. The design of railway infrastructure and overhead buildings should take the possibility of change into account. • Extendibility: A final step in flexibility is the possibility of extension. Both the infrastructure and the urban structures may require expansion. This is perhaps the most complex type. We shall discuss these four aspects of flexibility using examples of railway infrastructure and urban development.

5.6 Transport flexibility

Transport flexibility ensures that the railway infrastructure and the station will be able to meet changing requirements in the future. Flexibility can involve large investments, certainly for infrastructure. It is therefore important to design in a way that allows change at an acceptable cost, but with only limited pre-investment. Although this section will not be looking at finance, it is certainly important to maintain a balance between wishes and requirements regarding flexibility and the investment required to fulfil them. Pre-investment must be dealt with carefully, as often it just serves the decision-making process and is never used.

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5.6.1 Phase-ability Phasing for Phasing is especially important in the case of large-scale projects. Flexibility is required in construction of new railway lines order to speed up the project, to slow it down, or to change the plans during construction. alongside existing Because of the uncertainty inherent in projects with a time horizon of, for instance, 20 years, lines that remain it is necessary to so design projects that changes are possible. Although pre-investment in service at may be necessary to achieve this, such pre-investment must kept to a minimum, as it will not Bijlmer Station, Amsterdam always be used. Having said which, small pre-investments are justified when large changes [Coppermine] are likely at a later phase. Failure to take flexibility into account may render essential changes very expensive. Good phasing also makes it possible to delay a project when fewer resources < < are available temporarily, or when certain parts of the project prove unnecessary. Spatial Phasing of changes quality must be maintained at all stages, however, as one never knows when a project might to the railway sidings in the be delayed. Seine Rive Gauche project. The railway Examples of phasing the construction of new lines alongside lines that remain in service infrastructure is include Seine Rive Gauche and Amsterdam Bijlmer. Phase-ability should also take account of kept in service while parts of the the fact that railway operations continue during construction and that only a limited number infrastructure of possessions will be possible. are changed to facilitate the 5.6.2 Maintainability construction of buildings overhead. To ensure an acceptable level of track availability, it must be possible to carry out maintenance efficiently. This means being able to replace switches and crossings, track and other components of the railway system with minimal impact on the availability of the railway infrastructure. The overhead line, signalling system and other parts of the railway infrastructure must also be taken into account.

5.6.3 Changeability Changeability means being able to lengthen or widen platforms and move tracks and switches after the railway infrastructure has been built over. When designing an over- track structure, one must pay particular attention to the extent to which the building will allow later changes to the railway infrastructure. It is, however, very difficult to stipulate the degree to which such changes must be possible. To gain an insight into the situations that arise in practice, we shall look briefly at current changes to stations that have not yet been built over. Lengthening platforms is one of the most common forms of change. This allows the platform to accommodate longer trains, or two trains one behind the other.

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Extending Platform Lengthening platforms can hence increase the capacity of a station quite substantially. 15 at Amsterdam A number of platforms at Utrecht Centraal have recently been lengthened for this rea- Centraal has son, as have Platform 15 at Amsterdam Centraal and several platforms at Den Haag created extra

capacity Centraal. With these examples in mind, it is logical that railway infrastructure managers < < < may require platforms to be capable of extension. Widening platforms is another way of increasing the capacity of a station. However, this can require extensive changes to track Maglev is an example of a layout. It is possible to widen platforms in an existing station by removing tracks to create potential new sufficient space, e.g. when there is a third track between two platform tracks. The pos- transport system. sibility of moving tracks is an example of flexibility. The restrictions that apply to widening Shanghai is still platforms also apply to moving tracks within the station. In the area of the sidings, however, the only city with a Maglev in service. lateral displacement of tracks is logical. To make it possible to move tracks laterally in the future, it will be necessary to reserve space. In sidings, columns for overhead buildings can be placed between bundles of tracks in different directions. It must also be possible to modify switches to a certain extent. It may be useful to build infrastructure to a higher than usual structure gauge; the roofs of the tunnels on the Dutch Betuweroute freight line are all higher than usual, to allow the passage of double-stacked containers. Another form of changeability is the introduction of a new transport system. It is becoming increasingly common to use heavy-rail tracks for light-rail systems, as was done recently on the Rijn- Gouwe line in the Netherlands. Even incorporating a Maglev (magnetic levitation) system into large stations is not unthinkable in the long run. It is therefore advisable to think about these possibilities when building over tracks. This must not result in large pre-investments, but unnecessary restrictions on such possibilities should be avoided.

5.6.4 Extendibility Extendibility means that new platforms and tracks can be added to the station, horizontally or vertically. Large inner-city stations are usually directly surrounded by buildings on all sides. Extending the station sideways is only possible in specific cases where the land is not used or when existing buildings are demolished, as in the cases of London Waterloo or Brussel-Zuid. When there is land available beside the station, it may be worthwhile reserving it, because adding an extra platform is a common way of extending railway infrastructure. One example is ‘s-Hertogenbosch. In Utrecht, space was reserved under the Katreinetoren, so extra railway infrastructure could be added after the building had been constructed. In station areas where there is space to build beside the tracks, it may be worth reserving space for tracks on the lower floors. Until the space is required, it can function as a car-park, for instance.

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If horizontal extension is not possible, vertical extension may be, although horizontal is much Tracks under the cheaper. Vertical extension is possible by adding structures for new railway infrastructure Katreinetoren were constructed above the existing tracks. Because of noise and aesthetic considerations (visual barrier) after the building this is not the preferred option. Another possibility is that of building new tracks under the existing ones. The redevelopment of Antwerpen-Centraal is an example of this. New railway < < tunnels have been built at Levels -1 and -2 under the existing Level +1 tail tracks. Operations A third platform like Antwerp are rare because they are very expensive. When future urban development has been added to ‘s-Hertogenbosch over tracks is planned, one possibility is to keep options open for underground extension Station of the tracks. This can be taken into account when designing the foundations for the overhead structure. For instance, the foundations of the Stichthage building, at the beginning of the platforms at Den Haag Centraal, have reservations for future tunnels to accommodate through tracks for light rail.

It is also possible to provide for future tracks perpendicular to and below the existing ones. < Transverse Underground metro lines are often added underground extension of the at right angles to existing tracks, as in the infrastructure case of the north/south metro line under at Amsterdam construction below Amsterdam Centraal. Centraal Another example is Lehrter Bahnhof in Ber- lin, where two high-speed lines will cross at Levels +1 and -1 in the future. The grid of the foundations for the overhead structure can be adapted to future tunnels underneath. This means that the spans of the primary structure must not be too small, as that would restrict the positioning of a large part of the underground lines.

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5.7 Urban flexibility

Urban flexibility is necessary in order to add buildings in the future, change existing buildings or change plans. Buildings must be so designed that they can adapt to changing requirements. Urban flexibility has two scale levels: the area and the building. Buildings over railway infrastructure are more difficult to adapt to changes than are buildings beside the tracks. This makes the flexibility of such buildings even more important.

5.7.1 Phase-ability The phase-ability of large-scale urban plans is an important theme in the development of an area. It can take up to 20 years to develop a large area, and during that time user requirements, regulations and construction methods can change substantially. Given this uncertainty, it is necessary to take possible changes into account and to introduce enough flexibility to cope with them.

Urban flexibility is also necessary in order to anticipate changes in the station redevelopment plans. When plans are first drawn up, it is uncertain what the end result will be and how the project will evolve financially. For instance, the Broadgate project above and around Liverpool Street Station was broken down into twelve phases. Easy sites beside the tracks were developed first. The phasing made it possible to maintain the quality of the station area during most phases of rebuilding, and to build on other sites with only limited nuisance to the surroundings. The phasing that was chosen also had important financial advantages. Cash flows were generated in the first stages, to finance the more complex parts of the project. Market developments were also taken into account. In the Seine Rive Gauche project, pre- investments were made in the artificial ground level over the tracks, which could also be extended. Once that was complete, it was possible to build on the sites at this artificial ground level without disturbing the railway infrastructure.

5.7.2 Maintainability

The building < Maintainability is less decisive for buildings above the track at than for infrastructure – it is easier to replace Utrecht Centraal parts of buildings than to replace parts of the has balconies to enable infrastructure below. Nevertheless, main- maintenance tenance must be taken into account when designing a building over railway infrastructure. In most cases, tracks that are built over are among the most busy. They must not suf- fer interference from building maintenance, as the cost of taking them out of service is too high. The façade of the buildings above the track at Utrecht Centraal shows that it is possible to manage maintainability.

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5.7.3 Changeability The artificial The building and the railway under it must be completely separate functionally, so that modi- ground level over fications to the building do not disrupt railway operations. It is possible to achieve this func- the tracks at Seine Rive Gauche was tional separation by constructing a deck or a complete artificial ground level over the tracks built in several to take the building. Construction can then proceed without disrupting railway operations. phases, making This was the approach at Broadgate and Seine Rive Gauche, where the railway sidings were it possible to first covered by an artificial ground level, incorporating a transfer structure capable of sup- undertake changes to the buildings porting a twelve-storey building. Such a solution also makes it possible to place an entirely overhead while the new building on the same foundations with no disturbance to the tracks many years later. railway remained There will be load restrictions, however, and these will limit the height of any future building. in service Slightly over-dimensioning the artificial ground level is one way of increasing flexibility and < < allowing for a higher building in the future. Constructing an artificial ground level over all the A construction tracks gives the option of completely remodelling the area in years to come. It is possible that deck over in the initial situation only some of the foundation points will be used. Others may only be used the tracks at after the original buildings have been demolished, when new buildings replace them. This all Broadgate separates adds urban flexibility. construction work on the buildings Another form of changeability is the possibility of using a building for another function. This from the railway gives flexibility at the level of the whole area and at a building level. The building is flexible when service it can be used for more than one function. The functional arrangement of the area becomes flexible because the surface allocated to the different functions can be changed in the future. The ratio of offices to homes can be adapted to the needs of the city and the property market. It is worth noting that converting offices into flats is easier than the other way round, firstly because offices have fewer single owners to re-house than flats, and secondly because flats need fewer lifts than offices, which means that if one wishes to keep open the option of converting flats into offices one must install more lifts than would be required for flats. This has a negative effect on the ratio of gross to net floor space.

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5.7.4 Extendibility

Extendable < It may become necessary to increase the artificial ground density of an area that has already undergone level in Seine redevelopment. Further densification can be Rive Gauche made possible by arranging sites in such a way that they can be extended. Another approach is to design buildings that can be extended vertically. However, one should not create extendibility by leaving sites undeveloped, as it is important that the area have a ‘final phase’ quality level during all phases of use. In Seine Rive Gauche, extendibility was created by building in the possibility of extending the artificial ground level at a later stage.

5.8 Balancing quality and flexibility

The preceding sections have dealt with the quality and flexibility of railway infrastructure and the urban surroundings. However, these subjects are closely interrelated and influence each other. They must be balanced to achieve a design that best matches all requirements.

Quality Flexibilty < 2 Relationships Transport Transport quality Transport flexibility between quality 1 3 4 5 and flexibility, transport and Urban Urban quality Urban flexibility urban 6

5.8.1 Transport quality and urban quality Transport quality and urban quality have a positive relationship. Both can be achieved if the right design choices are made and if enough budget is available. However, tuning transport quality and urban quality to the same level demands some attention. If urban quality is higher than transport quality, this will highlight the lower transport quality and vice versa. A lower level of quality will also attract undesirable persons. This means that all the stakeholders in the station redevelopment project must be aiming for the same level of quality. Higher quality in one part of the project can have negative consequences for other parts. Furthermore, higher urban quality cannot compensate for lower transport quality or vice versa.

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5.8.2 Transport quality and transport flexibility To some extent, there is a conflict between transport quality and transport flexibility. To create flexibility for the railway infrastructure it is logical to over-dimension the structures, to take future changes into account. However, to create transport quality it is necessary to allow daylight to reach platform level and to create a good overview over the platforms. Transport quality therefore demands lighter structures. It is an advantage in this process that the trade-off between transport quality and transport flexibility is made by one stakeholder, the railway manager.

5.8.3 Transport quality and urban flexibility Transport quality has a negative effect on urban flexibility. Transport quality demands light, transparent structures, whereas urban flexibility requires over-dimensioned structures between and over the railway infrastructure, to allow for the high loads imposed by large buildings and to make it possible to build over the railway infrastructure at a number of locations. These requirements have to be balanced against one another.

5.8.4 Transport flexibility and urban quality Transport flexibility and urban quality have little influence on each other. Transport flexibility demands large spans over the tracks and few columns, but that does not necessarily make it impossible to achieve an acceptable level of urban quality. Large spans over the tracks can lead to landmark buildings, such as the Exchange House. If correctly designed, transport flexibility and urban quality can influence each other positively.

5.8.5 Transport flexibility and urban flexibility It is not possible to achieve transport flexibility and urban flexibility by a sum of measures, in contrast to transport quality and urban quality. The problem is that they are opposites. Transport flexibility demands large spans over the tracks, few columns – or even moveable columns – and enough headroom for the railway infrastructure. Urban flexibility demands limited spans over the tracks and extra (over-dimensioned) columns between the tracks. Every development project involving over-track construction therefore requires careful consideration of local requirements. This consideration is complicated by the fact that the requirements regarding flexibility are divided over a number of stakeholders. That has consequences for the process, as agreement must be reached regarding the extent of flexibility that will be incorporated into the design of the infrastructure and the urban environment. The contrast between sidings, where a high degree of flexibility is needed, and the platform area, which needs less flexibility, will also play a role in design considerations.

5.8.6 Urban quality and urban flexibility Urban quality is an essential precondition for a successful station area development project. Urban flexibility is a boundary condition, because the extent to which the requirements of the users are fulfilled depends on the ability to change and to meet these requirements during the lifespan of the project. Quality must be guaranteed during all phases. Urban flexibility can be a means of growing with the requirements, both qualitative and quantitative. Urban quality and urban flexibility are not in conflict; it is possible to maximise both if one makes appropriate design choices and has sufficient budget.

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5.9 Conclusion

This chapter discussed the quality and flexibility of development and redevelopment projects that involve building over railway tracks. Quality is needed to create a pleasant and crime-free space, while flexibility is needed to adapt to changing requirements and hence maintain quality in the future. As far as the station is concerned, building over railway infrastructure can be compared to building underground, with the difference that existing spaces need to adapt to a new underground environment. Aspects of quality and flexibility are divided over the railway infrastructure and the urban surroundings.

First of all, there is no recipe for quality. There is a lack of design guidelines that would ensure a high level of quality in the buildings over the railway infrastructure or a high level of spatial quality in the platforms underneath. However, there are certain indicators that can be of use in making a quick assessment. The ergonomics-based theories of Wijk & Luten can be used to assess the spatial quality of platforms. Lynch’s theory can be used to assess the urban surroundings, dividing the image of the city into five components.

In general, building over platforms has a negative effect on transport quality. Platforms that have been designed for an outside environment with a lot of daylight change into dark spaces when overhead structures block out that daylight. Based on Luten, the requirements regarding the spatial quality of these platforms are divided into structural, form, transfer and accommodation requirements, together making up the architecture. Platforms are always a transfer space, and if used for waiting they also have an accommodation function. A quick assessment of available reference projects showed that the quality of Dutch platforms is relatively poor compared to that of projects abroad. At the same time, there is a need for platforms in the Netherlands to be of higher quality, as Dutch stations are mostly through stations in which the platform area also functions as an accommodation space. Creating acceptable spatial quality for these platforms involves selecting optimal spatial proportions, adopting a sound functional platform layout that facilitates the transfer function, devoting sufficient attention to daylight and signage, achieving a good balance between daylight and artificial lighting and selecting the right type of finishing.

Urban quality is determined by the quality of the elements that determine the image of the city: paths, edges, districts, nodes and landmarks. From the assessment of available projects, we have examined examples of the integration of roads and streets (paths), the border between the redevelopment area and the existing city (edges), the combination of buildings that forms the station area (districts), the connection between the platforms and the urban surroundings and squares and parks (nodes), and different types of building as landmarks (landmarks).

Flexibility is also divided into transport flexibility and urban flexibility. There are different types of flexibility: phase-ability, maintainability, changeability and extendibility. On the basis of reference projects, we have looked at examples of how to integrate all these types of flexibility into future projects. Because flexibility usually requires extra investment, it is necessary to examine carefully the need for measures to achieve extra flexibility. The trick is to make small pre-investments that limit the future cost of change.

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Quality Flexibilty < Positive and negative 2 relation-ships Transport quality Transport flexibility Transport between quality 1 3 4 5 and flexibility, transport and Urban Urban quality Urban flexibility urban. The positive 6 relationships are indicated by green arrows and the negative Finally, this chapter has looked at the balance between flexibility and quality, for the railway relationships infrastructure and the surrounding city. Transport flexibility, transport quality, urban flexibility by red arrows. and urban quality are all related to one another, which can be positive as well as negative. The negative relationships make it clear that the design must so balance the different types of flexibility and quality as to produce a result that best matches all requirements.

Quality and flexibility can be seen as ‘soft’ design requirements for new building over railway infrastructure. The next chapter will deal with ‘hard’ requirements for such structures, namely the technical aspects. That chapter will mainly look at noise, vibration and electromagnetic compatibility.

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Chapter 6 Technical aspects

Moving on from the ‘softer’ aspects of designing property developments over railway infrastructure, this chapter will focus on the technical aspects. We shall be addressing noise, vibration, electromagnetic compatibility (EMC) and other technical aspects of building over and near railway tracks. This chapter will go into some detail on noise, vibration and EMC, describing the problem, discussing legal issues and reviewing recent research. We shall then outline countermeasures that can be applied at various points between the source and the victim of the nuisance. Discussion of other technical aspects will remain brief. It is necessary to be familiar with these technical problems and corresponding countermeasures in order to set the technical boundary conditions for building over and near the track. While one could see physical safety as a ‘technical aspect’, we have devoted a separate chapter (Chapter 7) to this issue on account of its importance.

6.1 Railway noise

It is necessary to prevent noise and noise nuisance from railway traffic inside buildings above or beside the track. As part of the present doctoral research, Jacobs studied the vertical distribution of noise at buildings over railway tracks for his degree dissertation [Jacobs, 2002]. This section uses the results of his work, together with regulations and measures concerning noise nuisance.

6.1.1 Problem description Many studies have examined noise nuisance due to railway traffic. There is also an extensive legal framework. Dutch regulations prescribe the use of Standaard Rekenmethode II (SRM II, standard calculation method II) to determine the noise impact of railway traffic on adjacent buildings. For buildings adjacent to the track, this method is satisfactory. However, nothing is currently known about vertical distribution of noise from trains, whereas this is precisely what we need to know in order to determine the noise impact on buildings above the track.

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Jacobs was the first to study the vertical distribution of railway noise in the Netherlands, and little work has been undertaken in this field elsewhere.

SRM II assumes that the vertical distribution of railway noise is the same as the horizontal distribution. The method takes no account of the fact that the upper part of the train masks the noise of its own wheels and thereby limits the vertical distribution of noise. In other words, trains emit less noise vertically than horizontally. Attenuation is likely to be greatest at an angle of ninety degrees, i.e. directly above the train. Taking account of the fact that trains emit less noise vertically than horizontally would favour construction over railway tracks, as the measures demanded to protect over-track buildings would be less onerous than those stipulated for buildings beside the track. A building that spans several tracks would benefit less from the attenuation of vertically-transmitted noise, as such buildings are subjected to a combination of horizontal and vertical noise.

Expected Noise distribution < Expected vertical noise distribution according to SRM-II and horizontal noise distribution (left) compared with noise distribution calculated using SRM II (right) [Jacobs]

6.1.2 Legal issues In the Netherlands, noise emission is regulated in the Wet Geluidhinder (noise pollution act) and the Besluit opslag- en transportbedrijven Milieubeheer (environmental regulations on transport and storage companies). The Wet Geluidhinder results from the Wet Milieubeheer (environmental act) and is closely linked with the Wet op de Ruimtelijke Ordening (town and country planning act). The Wet Geluidhinder sets limits for noise levels on the outside surface of buildings and inside them. The Besluit opslag- en transportbedrijven Milieubeheer also results from the Wet Milieubeheer. These regulations regulate noise emission from railway yards and their effects on buildings in the vicinity. The present study will focus on the level of noise generated by railway traffic and by marshalling operations in railway yards. Maximum permissible noise levels on the exterior walls of buildings and inside them vary according to

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Technical aspects < Preferred maximum Maximum dispensation Maximum interior Limits on noise noise level noise level noise level levels for the exterior walls and interiors of new buildings under the Noise Pollution Act

the function of the building. Limits are lower for dwellings than for offices, for instance. The Wet Geluidhinder gives a preferred maximum for noise measured at the exterior wall, a maximum dispensation limit on the outside surface and a maximum for inside the building. These limits apply to new buildings; regulations for existing buildings are less stringent.

If noise is below the preferred maximum, any type of development is permitted. If the noise level exceeds the preferred maximum but remains below maximum dispensation level, it is possible to obtain an exemption in certain cases, enabling development to take place. One example of this is the building of dwellings near stations. Here, it will be stipulated that the arrangement of the dwellings be adjusted to take account of the noise nuisance. For instance, sound-sensitive rooms can be placed on the sheltered side of the building. If an exemption is granted, it will still be necessary to take countermeasures in order to stay within the maximum interior limit. Buildings inside the ‘maximum dispensation limit’ zone (70 dB(A)) must have an exterior wall with no parts that can be opened.

The Woningwet (housing act) specifies the degree of sound attenuation that the exterior wall must provide. The Bouwbesluit (buildings decree), an implementing order under the Woning- wet, requires that the noise attenuation of the outside wall conform to Dutch standard NEN 5077. A specific measurement method is prescribed, and measurements in accordance with that method are carried out once the building is finished.

6.1.3 Noise sources on trains A train has three main noise sources, and it is these sources that determine the noise nuisance that the train causes to its surroundings: • system noise; • wheel-rail noise; • aerodynamic noise.

These three sources of noise have different intensities and radiate at different angles. The speed of the train determines which source is dominant [Dool & Breugel, 2003]. Up to 30 km/h or 40 km/h, system noise dominates. Up to 250 km/h it is wheel-rail noise and above 250 km/h it is aerodynamic noise that dominates.

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< Different noise 120 sources on trains and their dominance at 110 different train speeds [EC]

100 Sound level [dB(A)]

Total 80 System

Wheel/rail Aerodynamic 70 10 20 50 100 200 300 400

Train speed [km/h]

System noise: The system noise of a train comes from a number of sources. These include: • the static converter that converts the direct current of the overhead line into alternating current; • the compressors for the braking system and the doors; • ventilation for traction cooling and the ventilation grille for air conditioning. System noise is distributed via gratings and vibrating surfaces. This distribution is assumed to be omnidirectional, so there is no difference between the noise level beside the train and above. This type of noise nuisance is mainly a problem around railway yards.

Wheel-rail noise: Wheel-rail noise is the most complex train noise source. Furthermore, the vertical radiation of this type of noise differs from the horizontal. There are three types of wheel-rail noise: • rolling noise; • squeal; • impact noise. Rolling noise is caused by irregularities in the wheel-rail contact patch. Squeal arises when the flange of the wheel slides along the rail as the train negotiates curves. The tight curves in sidings and yards make squeal a significant problem at such locations, whereas curves on open track are more gradual and squeal is less of an issue. Impact noise arises from large irregularities in the rails. The upper part of the train masks wheel-rail noise vertically. This reduces the noise level at the exterior walls of buildings above the train.

Aerodynamic noise: Aerodynamic noise dominates at train speeds above 250 km/h, i.e. for high-speed trains. This is therefore not the dominant noise type when building over railway tracks, as we are unlikely to encounter train speeds of 250 km/h in the inner cities where projects involving

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multiple use of space are under consideration. Aerodynamic noise is caused by air flows and whirling streams along the external components of the train, and by the pantograph. While there are many studies on aerodynamic noise, there is no data on the difference between vertical and horizontal transmission.

Wheel-rail noise is the type of noise for which the difference between the levels at exterior walls above the track differs most markedly from levels at exterior walls beside the track. Jacobs has studied the reduction in wheel-rail noise as a function of angle relative to the horizontal, using measurements taken outside the Netherlands. Jacobs has also conducted field measurements and built a model to study the directional distribution of wheel-rail noise.

6.1.4 Results for vertical noise emission The research shows that available calculation models over-estimate the vertical emission of railway noise. On the basis of international research [Lang, 1989] and measurements by Jacobs [Jacobs, 2002], it can be concluded that a reduction of 4 dB(A) is possible for freight trains and 7 dB(A) for passenger trains, compared to the results of SRM II. Wheel-rail noise is also the dominant source of vertical noise emission from trains and the difference between horizontal and vertical emission does not depend on the distance from the track. The emission characteristic depends in part on the speed of the train.

The noise level on the exterior wall above the track will be lower than that calculated by SRM II. This means that the noise level on an exterior wall above the track is lower than that on an exterior wall at the same distance from the track but at track level. However, we must Noise barriers take into consideration that an exterior wall above a track will be closer to the train than an are often used to exterior wall at track level. reduce noise levels at surrounding

buildings 6.1.5 Countermeasures, from source to recipient < < < Where the noise level on the exterior wall is too high, it is possible to take countermeasures at the source, along the transmission path and at the recipient. At the source, it is possible A rail damper to use rail dampers, which can reduce noise emission by between 2 dB(A) and 7 dB(A) [KWS, can reduce noise 2005]. In the transmission path, it is possible to use noise barriers. In some cases, these emission by between 2 dB(A) may need to be up to 9 m high. When buildings near railway tracks are higher, or when they and 7 dB(A) [KWS] are closer to the tracks, the noise barrier must be even higher. <

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Het Funen, a block of flats in Amsterdam, has no opening windows on the side nearest < the track

< A housing project beside the A1 near Bussum, with no opening windows on the side nearest the motorway

126 Technical aspects

The exterior wall of an over-track building can be partly screened by a horizontal structure directly above the track. As well as constituting a noise screen, it will act as a safety measure during construction, serving as a crash deck. If the noise level on the exterior wall of a flat remains in excess of 70 dB(A), it is still possible to build a wall with no doors or opening windows. This wall can be of glass to provide a view to the users, as in the Funen project in Amsterdam.

6.2 Railway vibration

The passage of a train causes vibration in buildings above or beside the track. Vibration can damage the structure and can degrade the comfort of the people in the building. Vibration from passing trains is a complex area of research. Leijendekker studied vibration nuisance in a hotel over railway tracks in Amsterdam for his degree dissertation [Leijendekker, 2003]. This section uses parts of his results.

6.2.1 Problem description Vibration from passing trains affects both the building and its users. It can damage the building, e.g. by causing cracking. It can also affect people, in four ways: physiological impact (at high intensities), psychological impact (a fear of impact), operational impact (disturbance of activities) and disturbance of rest [Gezondheidsraad, 1994]. The impact of vibration must be limited to an acceptable level. The number of train movements has increased, but at the same time so have expectations regarding ‘user friendliness’. This is especially true with respect to buildings such as hospitals, concert halls and hotels [Hock-Berghaus, 2001].

Apart from structure-borne vibration nuisance, there is nuisance in the form of low-frequency sound. Low-frequency sounds are those with components at the bottom end of the audible range [Soede, 2001]. They can be detected by the ear, by pressure in the auditory canal and the head, and by vibration in the stomach and chest. How these low-frequency sounds are perceived depends on their characteristics. A ‘rustling’ low-frequency sound is more easily perceptible than one in which a single frequency stands out. When one frequency does dominate, cups on a table or windows may vibrate.

6.2.2 Legal issues There are no laws governing nuisance from railway vibration. However, in certain cases it will be necessary to determine the vibration nuisance objectively. To enable objective measurement of vibration nuisance in rooms and spaces, the SBR (a Dutch building research organisation) has produced SBR Guideline B [Staalduinen & Vecht, 2002]. This document contains guidelines on measurements and assessments to determine the vibration nuisance suffered by building users. It does not take low-frequency sound into account.

The guideline distinguishes between five types of building function and four types of vibration. Buildings are divided into: health care, living, office and education, meeting place and critical workspace. Vibration is classified as: continuous long-term, repeated long-term, continuous for less than three months and incidental short-term. The second category is important for

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railway traffic and the third category for the construction process. We shall not look at this third category here, as the construction of a new building does not cause a nuisance to its new users and doesn’t differ from other inner-city property developments. Target values have been established for the five building functions and the four types of vibration. These values distinguish between a maximum value for daytime (07.00 – 19.00), evening (19.00 – 23.00) and night (23.00 – 07.00). The target value is respected if the average vibration intensity is lower than A1, or the maximum vibration intensity is lower than A2 for a short period of time in combination with an average vibration intensity lower than A3. Vibration is measured in terms of speed, in mm/s.

Daytime and evening [mm/s] Night [mm/s] < Target maximum Building function A1 A2 A3 A1 A2 A3 intensity values for Health care 0.1 0.4 0.05 0.1 0.2 0.05 vibration occurring Living 0.1 0.4 0.05 0.1 0.2 0.05 repeatedly over a Office and education 0.15 0.6 0.07 0.15 0.6 0.07 long period Meeting place 0.15 0.6 0.07 0.15 0.6 0.07 Critical workspace 0.1 0.1 – 0.1 0.1 –

A report by the Dutch Health Council (Gezondheidsraad) indicates that foreign standards and directives on vibration intensity are mainly based on practical experience and feasibility [Gezondheidsraad, 1994]. There is only a small amount of scientific data. The Netherlands has no specific legal standards for low-frequency sound. The Noise Pollution Act gives a marginal value, but this marginal value has no stipulations regarding spectral content, i.e. the different frequencies present in the vibration [Soede, 2001]. We have found no standards for low-frequency sound outside the Netherlands.

6.2.3 Research description Leijendekker’s study on a hotel over railway tracks near Amsterdam Centraal involves < Source, modelling railway vibration through source, transmission transmission and recipient in a finite element and recipient of railway vibration model. The data for the vibration source was in a hotel over derived from field measurements at the site railway tracks of the planned hotel. The passage of a freight train was chosen as a representative source of vibration nuisance; because of their weight, freight trains generate low frequency vibration, which has the greatest influence on the structure. The transmission of vibration through the soil and the foundations was modelled using the GEOVIB model and a railway track model (both produced by

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Holland Railconsult, now Movares). The building subjected to the vibration was modelled in ANSYS. The reaction of a structure to railway vibration is a function of mass, stiffness and damping. These parameters were incorporated into a dynamic movement equation. The effects of differences in building structure were studied by varying the stiffness of the elements, their mass, the damping of the whole structure and the connections between beams and columns.

6.2.4 Research results The excitation frequencies with the highest energy content lie between 5 Hz and 25 Hz [Leijendekker, 2003]. Vibration from heavy freight trains lies at the lower end of this frequency range. Lighter rolling stock, such as metro trains, has a higher frequency range. Vecht indicates a spectrum of 20 Hz – 100 Hz for railway traffic [Vecht, 2003]. A disadvantage of building near railway tracks compared to metro tracks is that a railway carries different types of rolling stock, with different frequency ranges, whereas a structure can only be designed to react optimally to a single frequency. A normative frequency must be chosen. Generally, one chooses the lowest frequency – that generated by freight trains – because excitation in the 3 Hz to 12 Hz range emanating from freight trains is closest to the natural frequency of buildings, and excitation at frequencies close to the natural frequency of a building can cause vibration problems.

By means of the variation study, Leijendekker demonstrated that varying stiffness has only a small influence on the effective vibration speed [Leijendekker, 2003]. To affect the vibration behaviour of the structure, it is necessary to modify the stiffness of large parts of it. Weakening the structure has a positive effect, as reducing stiffness lowers the normal frequency. Increasing the mass at strategic locations in the building can also considerably reduce the effective vibration speed in the structure. Increasing the weight of the upper floor has a positive effect, for instance. However, varying stiffness and mass can conflict with the statics requirements for the building.

Leijendekker noted that increasing damping within a structure also reduces effective vibration speed. One way to increase damping is to incorporate friction connections, which damp structural vibration by dissipating energy. It is possible to damp steel structures using bolted connections.

6.2.5 Countermeasures, from source to recipient Vibration has a source, a transmission path and a recipient. We must take all three elements into account when considering measures to reduce vibration. Building over railway tracks is most common in existing inner-city areas, where it is generally difficult to take action at the source of the vibration or along the transmission path through the earth. We must therefore focus our efforts on the recipient – the projected new building over or beside the track.

Which countermeasures will be most cost effective depends to a large degree on the number of buildings affected. Where there are many buildings, measures at the source are cost effective, while measures in the buildings or along the transmission path are cost effective where there are fewer buildings.

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Countermeasures at the source involve isolating the rail system. Such measures are particu- Section of a larly logical when building or replacing a track. There are several ways of isolating the rail sys- mass-spring system below the tem; the easiest is to use a track structure that does not readily transmit vibration. A second track [GERB] option is slab track. The most effective measure, but also the most expensive, is a floating slab: a mass-spring system or one in which the track rests on rubber blocks [GERB, 2001]. < < Measures at the It is also possible to take countermeasures along the transmission path. Jaquet & Heiland source of the vibration: a mass- divide the transmission of vibration into the introduction of vibration into the ground, its spring system passage through the ground and its introduction into the building [Jaquet & Heiland, 1994]. [GERB] Herrmann and Wagner state that countermeasures are rarely applied along the transmission path because they are controversial [Herrmann & Wagner, 2002]. Measures against the introduction of vibration into the ground are source-side measures, whereas measures against the introduction of vibration into the building are recipient-side measures. Foundation on rubber mats in It is possible to limit the transmission of vibration through the ground by building a screen in the Eemstroom the ground (a sheet-pile wall or a trench) at some distance from the tracks, to disrupt the housing project vibration [Gardien, 2003]. [Peutz] < < Countermeasures at the building can take a number of forms. It may be possible to modify One of 30 springs the way the building vibrates. On the basis of the study mentioned above, it is possible to installed under Sydney Conservatory vary the mass, stiffness or damping of the building. Such measures are not necessarily to reduce vibration expensive if incorporated at the design stage. It is also possible to isolate the foundations from the metro of the building [Gardien, 2003]. [GERB] <

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Further measures on the recipient side include elastically isolating the building, parts of the building, or specific spaces within a building from the vibration [Herrmann & Wagner, 2002]. Examples of such measures include rubber supports and springs. Springs can be geared to the normal frequency of the structure (between 3 Hz and 5 Hz) in such a way as to block low-frequency sound and considerably reduce vibration at frequencies of between 10 Hz and 20 Hz [Hock-Berghaus, 2001]. These measures can reduce such vibration by up to 80% or 90%. Similar effects are possible using rubber blocks or mats. However, these have a higher normal frequency, closer to the vibration frequency. They are cheaper and demand less maintenance than springs, making them more cost-effective. Rubber mats were used for the Eemstroom housing project near Amersfoort, while springs were used for a block of flats above Rijswijk Station [Vecht, 2001] and for Sydney Conservatory [GERB, 2001].

Choosing cost- < Situation Many buildings Few buildings effective measures Area on which to focus Source Transmission path Recipient against vibration (track) (ground) (building) Countermeasures Track structure Sheet-pile structure Structural measures Slab track Rubber mats Floating slab Springs

Countermeasures at the source are more cost-effective where there are many buildings, whereas countermeasures directed at the transmission path or the recipient are more cost-effective where there are fewer buildings. Within each set of countermeasures – source and recipient – we can again classify particular measures as more or less cost- effective. However, this assessment of cost-effectiveness is merely an indication, based on the fact that rubber mats are usually cheaper than springs and the assumption that measures affecting the structure will not incur excessive additional cost.

6.3 Electromagnetic compatibility

The passage of trains and the current in the overhead line cause electric and magnetic fields. These can interfere with electrical equipment in buildings above or beside the track. Electromagnetic compatibility (EMC) is the capacity of a system to function satisfactorily in its electromagnetic environment without adding intolerable interfering signals to that environment. Holland Railconsult (now Movares) has conducted research in this field [Janssen, 2001] and this section uses the results of that work.

6.3.1 Problem description Both operation of the existing 1.5 kV d.c. traction system and the introduction of new systems, such as the 25 kV/50 Hz a.c. system for the HSL-Zuid, can lead to EMC problems in combination with reduced distances between the railway system and its surroundings. EMC problems can affect people and equipment. Such problems include jamming other equipment or influencing people in ways that lead to dangerous or unhealthy situations. Examples include computer monitors flickering or failing to display the correct colours, or a car detection loop detecting cars that are not there or failing to detect those that are.

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50 < Magnetic fields 40 around a double- 3 track railway

30 line with a 25 kV return

20 transformer 10 system

10 30

1 -10

1 -20 1 -50 -40 -30 -20 -10 0 10 20 30 40 50

Plans to build a railway line close to buildings may be a reason for protest, even if it is placed at a sufficient distance. Occupants may be opposed to a new railway line for health reasons, such as fear that magnetic fields will cause leukaemia, insomnia or other problems. Even though research has yet to produce convincing arguments in support of that fear, fear as such is a nuisance that should definitely be taken into account.

Coupling is the mechanism whereby interference is transmitted from a source (the railway system in this instance) to the recipient (in this instance, systems or people near the track).

There are three types of coupling with respect to EMC: • magnetic fields (H fields); • electric fields (E fields); • galvanic conductivity (current).

Magnetic fields arise as a result of a current flowing in a conductor. This includes not only the current in the overhead line, but also that in the return circuit (e.g. the track). Current flowing through a conductor also creates an electric field. In the railway environment, the overhead line is the main source of such fields. Coupling by means of galvanic conductivity occurs when part of the current leaks out of the return circuit and flows to where it was not intended to. These are called stray currents. The three types of coupling can be subdivided into low-frequency, medium frequency and high frequency (LF, MF and HF).

6.3.2 Legal issues There are international regulations on EMC, and these have been adopted as a Dutch standard. There are also directives concerning the immunity of the recipient and emission from the track system. The international directives are laid down by the International Electrotech- nical Commission (IEC). As far as immunity is concerned, the standards distinguish between two types of environment: Domestic, trade and light industrial, and Industrial. Standard 61000-6-1 applies to the former [IEC, 1997 and NNI, 2001a]. Standard 61000-6-2 applies to the latter [IEC, 1999 and NNI, 2001b]. Standards 50121-1 [NNI, 2000a] and 50121-2 [NNI, 2000b] apply to emissions from a railway system into its surroundings.

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The standards use three categories, based on performance criteria:

Criterion A: The device functions correctly under all circumstances. The producer can possibly specify a certain loss of performance. Criterion B: The device functions correctly after the test, but disturbance may occur during the test. The device must, however, function correctly after the test without manual intervention (e.g. resetting). Criterion C: The device may experience disturbance during the test, but must function correctly afterwards following intervention (e.g. turning the device off and on or pushing a reset button).

6.3.3 Research description Study of EMC in buildings near railway tracks covers four areas [Janssen, 2001]: • low-frequency magnetic fields; • low-frequency electric fields; • higher-frequency electric and magnetic fields (electromagnetic waves); • galvanic flows through the soil.

In each area, the study distinguishes between 1.5 kV d.c. and 25 kV/50 Hz a.c.

Low-frequency magnetic fields are caused by the passage of trains. The traction current in the overhead line and the return current in the rails contribute to the total magnetic field. A changing magnetic field induces a voltage in a loop of conductive material, which in turn may cause a dangerous charge. Moreover, devices sensitive to magnetic fields may be influenced. The type of device most commonly affected is the CRT screen. Problems for persons are unlikely.

Low-frequency electric fields result from the current in the overhead line and the negative feeder (the latter applies only to the 25 kV/50 Hz system). They do not cause interference to most devices. The largest source of low-frequency fields is the traction current, which generates fields not only at its fundamental frequency but also at harmonics, i.e. multiples of the fundamental. For instance, a train can produce fields with frequencies of 150 Hz and 250 Hz (third and fifth harmonics) from a 25 kV/50 Hz supply. Short-circuits are also classed as low-frequency phenomena. However, they are of short duration and can only cause short- term interference. Whether this is acceptable depends on the function of the recipient. It is generally acceptable if a CRT screen flickers briefly, whereas such interference might be unacceptable elsewhere, such as in medical equipment.

Medium-frequency and high-frequency electromagnetic fields are mainly caused by arcing between the pantograph and the overhead line. The intensity of such fields depends on a large number of parameters, such as contact pressure, speed and weather conditions (e.g. ice). Medium-frequency fields have a larger magnetic component, whereas at high frequencies the electric and magnetic fields combine in a fixed ratio, with the electric field the more relevant.

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Galvanic conductivity arises because some of the current finds its way through the soil instead of through the return circuit. This is in itself no problem if it has been taken into account at the design and construction stages. It is possible for current in the concrete reinforcement to produce a larger magnetic field than the current in the track itself, but this is unusual.

6.3.4 Research results The study on EMC problems in buildings near railway infrastructure resulted in an overview of the relationship between distance from the infrastructure and the impact of the electromagnetic fields it produces. The 1.5 kV d.c. and 25 kV/50 Hz a.c. traction systems were examined separately, each for a double-track line. The study also distinguishes between a domestic environment where people are present 24 hours a day, a domestic environment where people are present 8 hours a day and an industrial environment. Finally, a distinction was made between the areas above, under and beside the tracks, defined relative to top of rail. The distances calculated depend on the local situation. Results also vary when there are several adjacent tracks; the resulting fields will be greater than those from a single track.

6.3.5 Countermeasures, from source to recipient The options for protection against low-frequency magnetic fields are limited. It is possible to attenuate such fields by a factor of three by using large amounts of steel, and attenuation is greater when µ-metal is used (here, µ represents magnetic conductivity). µ-metal is a special alloy that shields against magnetic fields. However, it is expensive and delicate. Replacing CRT screens by LCD panels is another, more cost-effective way of preventing interference from magnetic fields. Active compensation is also possible, by creating a magnetic field that compensates for the interfering magnetic field. This is possible both for small objects and for large spaces.

A low-frequency electric field can simply be screened by a metal housing. Concrete reinforcement also provides effective attenuation, acting as a Faraday cage. However, the Faraday cage effect gives no protection against magnetic fields.

For medium-frequency and high-frequency electromagnetic fields, attenuation of 40 dB is needed to guarantee electromagnetic compatibility [Janssen, 2001]. Attenuation is measured in dB (not the same as the dB used to measure noise emission). If no attenuation is introduced, equipment must be 25 m from the centre of the nearest track to escape electromagnetic interference from the double-track line modelled for Janssen’s study. Concrete provides 10 dB to 30 dB attenuation [Goedbloed, 1999]. Timber, brick and glass provide very little.

In addition to technical measures (choice of materials) it is also possible to achieve EMC by changing the layout of buildings above or beside the track. Sensitive equipment can be located further from the track and less sensitive functions closer. It is also advisable to run wiring in metal ducts. Trying to avoid electrical connections between elements of the concrete reinforcement is not a useful way of limiting conductivity; such measures may well lead to local concentrations. If the reinforcement is properly connected electrically, conductivity will be distributed evenly.

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6.4 Other technical aspects

Two other technical aspects play a role in property development near railway tracks: wind nuisance and air quality. We shall look briefly at these issues in this section.

6.4.1 Wind nuisance Wind nuisance will present a problem when we build over railway tracks at ground level or higher. Building over the track will create a new artificial ground level, 10 m above original ground level. Wind at this altitude can be very unpleasant and even dangerous. High buildings or structures in close proximity to one another can lead to similar problems. In the case of high-rise buildings, problems usually occur at the base. We can avoid wind nuisance by so guiding the wind as to prevent high wind pressures developing. The arrangement of buildings can be so designed as to minimise wind nuisance. For instance, we can place high-rise buildings on a broader base to create a favourable wind climate at ground level. We can prevent wind nuisance at the new, artificial ground level using wind screens.

A specific point of attention is the air pressure generated by passing trains. This can be dangerous for people on platforms and is also a problem when trains enter and leave tunnels. Air pressure from fast trains can even damage structures (e.g. noise barriers) because of dynamic loads.

Wind screens 6.4.2 Air quality limit wind nuisance Railway traffic causes air pollution on a very local scale in the form of metal particles. Friction for passengers in Duivendrecht between the contact wire and the pantograph releases copper particles into the air, while station, which lies the interaction between wheel and rail generates iron particles. Copper particles can be about 10 m above sucked into ventilation systems because they are very small (< 1 mm), as a result of which ground level they will behave like a gas [Cauberg, 2001]. These particles will influence the air quality in

on a dike < < < the building. Iron particles are larger and will settle on surfaces within approximately 10 m of the track [Cauberg, 2001]. Metals will have an effect on surrounding buildings, because they Wind screens cause corrosion to other metals. Building over railways generates relatively closed spaces, under the Grande so it will be necessary to take this problem into account, mainly from a maintenance point of Arche in Paris limit wind nuisance view. These particles also damage the finish of cars parked near stations and may detract for visitors from the appearance of buildings near the track, including stations. <

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6.5 Conclusion

Technical aspects determine technical boundary conditions for the design of buildings over and near railway tracks. This chapter discussed three important technical aspects (noise, vibration and electromagnetic compatibility) and briefly mentioned two others (wind nuisance and air quality). The link between noise, vibration and EMC lies in the fact that they all have a source, a transmission path and a recipient that can be analysed and for which practical, cost-effective countermeasures can be found.

Noise nuisance is a common problem for property development near infrastructure in general. However, there is an interesting difference between buildings over railways tracks and buildings over other infrastructure: trains emit less noise vertically than horizontally. This is an advantage when building over railways, because the noise load on external walls above the track is lower than presently calculated by standard calculation methods. It is possible to limit noise nuisance at source (e.g. using rail dampers), along the transmission path (noise screens) and at the recipient (not installing opening windows, if necessary).

Vibration is a greater challenge. The variety of train types makes it difficult to predict either the way in which vibration will pass through the ground and structures or the dominant vibration itself. This chapter has presented a broad palette of measures, from which it is necessary to choose carefully in the light of local conditions. Where there are many buildings near the track, measures at the source are cost-effective. Otherwise, it is preferable to take measures at the recipient (the building itself) or along the transmission path through the ground.

EMC is an area in which it is difficult to predict effects. It is not easy to establish the correlation between low-, medium- and high-frequency electric and magnetic fields, or their effects. Countermeasures have limited effect. However, it is possible to enhance EMC by taking account of the question at an early stage of design. Technical measures include using LCD screens or Faraday cages, although the latter only offer protection against electric fields, not magnetic. One functional measure is to so design the building layout as to place as much distance as possible between equipment sensitive to electric or magnetic fields and the railway infrastructure that produces them.

This chapter has shown that there is no such thing as a general package of technical measures applicable to every project involving property development over or near railway infrastructure. The effectiveness and cost-effectiveness of a measure will depend on the local situation. We shall use the results of this study on technical aspects in Chapter 8 when we look at structural design. First, however, the next chapter will examine physical safety, a factor that has a major impact on the scope for developing property over and beside railway tracks.

136 Introduction

Chapter 7 Physical safety

Physical safety is a specific technical aspect. It plays an important role in all construction over or near railways, and in many cases will be one of the most important issues, mainly because of the transportation of hazardous goods. This chapter on physical safety will focus on external safety, i.e. the risk that railway operations pose to new property over or near the track. We shall combine approaches to physical safety, rules, regulations and recent developments, integrating them into a new concept of physical safety in and around railway stations. This concept is named the HR-3D method, of which HR is derived from Holland Railconsult, now Movares, and 3D because it approaches safety in all three spatial dimensions. We shall then show how this HR-3D method has been applied to three real-life projects.

7.1 Physical and social safety in spatial design

Railway stations are often redeveloped to create a liveable space. ‘Liveability’ has two sides: spatial design and safety. Spatial design is a ‘satisfier’; good spatial design confers added value. Safety is a ‘dissatisfier’; future users demand that the design guarantees their safety and they will not accept the absence of safety. Recent disasters in the Netherlands such as the fireworks factory explosion in Enschede (2000) and the café fire in Volendam (2001) underline this point. The challenge facing designers of station redevelopments is to create a good spatial design within the framework of physical safety. However, regulations on physical safety include many blind spots [Vambersky, et al., 2002] and it is the designer’s task to make a good assessment of both spatial quality and physical safety.

Physical safety has become a crucial point in the appraisal of urban plans. Some plans are limited because of safety regulations and others are so downsized to match these regulations that they fail to meet expectations regarding revenue and spatial quality. Examples are found in Eindhoven and Dordrecht and will be discussed later on. The Dutch government is developing

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policy that may help counter this problem. The first step was publication of the report Verant- woorde risico’s, veilige ruimte (sound risks, safe space) by the Advisory Council for Transport, Public Works and Water Management in collaboration with the Advisory Council for Housing, Spatial Planning and the Environment [VROM & V&W, 2003].

In the Netherlands, individual risks are currently evaluated using risk contours. A risk analysis is made and the result is a contour within which the development of vulnerable functions is prohibited. The main factor determining the contour is the quantity of hazardous goods on the transport axis.

7.1.1 Statistics on railway safety Train travel is very safe compared to other types of transport. Witsen [2002] states that no other form of transport is as safe as the train and no other form of transport has such high safety requirements.

Number of casualties per Number of casualties per 100 million km travelled 100 million hours travelled < Safety of rail travel versus other Motorbike or moped 16.00 Motorbike or moped 500.0 modes of transport Pedestrian 7.50 Bicycle 90.0 [Witsen, 2002] Bicycle 6.30 Aircraft 36.5 Car 0.80 Car 30.0 Ferry 0.33 Pedestrian 30.0 Aircraft 0.08 Ferry 10.5 Bus or coach 0.08 Bus or coach 2.0 Train 0.04 Train 2.0

Railway accidents are rare, but when they do occur they can easily have a huge impact. A collision near Public aversion to single accidents with a large number of victims can quickly lead to a nega- Amsterdam tive impression of safety. Accidents in one country are discussed in the media of others, Centraal in May drawing extra attention to the risks of accidents on infrastructure. The available statistics 2004 [Parool] for accidents and near-accidents have been used to produce a model for calculating exter- < < nal safety, external safety being the risk of people around the railway infrastructure dying A train on fire because of a railway accident. Because of the limited availability of data (large accidents near Hoofddorp rarely happen) this is not a detailed risk calculation, more a |speculative approach. [Parool] <

138 Physical safety

7.1.2 Railway accidents: statistics It is difficult to make a valid statistical analysis of railway accidents in the Netherlands as there are so few of them. Nonetheless, trains do derail, collide or catch fire with a certain regularity. The main problem with railway accidents is that they usually have a huge impact, both on people and on the economy. Even when there are no victims, railway accidents have an impact on the whole railway system and can cause major economic damage. A collision between two trains near Amsterdam Centraal in May 2004 is a recent example. Trains can also catch fire, as the picture illustrates.

So far, there have been no serious accidents

Leakage of < involving hazardous goods on the Dutch rail acrylic nitrile near network. However, disasters on the roads Amersfoort Station affect assessment of the dangers involved in August 2002 led to the evacuation in the transport of hazardous goods. While of an area with a no hazardous goods accidents on the Dutch radius of 500 m railways have ever caused large numbers of [Parool] victims, near-accidents do take place with some regularity, which means that a major disaster is not just a theoretical risk. On 20 August 2002, an area with a radius of 500 m was evacuated, because a stationary train was leaking acrylic nitrile near a station. The quantity of acrylic nitrile that leaked out was not even close to the quantity required to cause harm, but the railway network in the centre of the Netherlands became almost completely inoperative [Parool, 21-08-2002].

There is no information on accidents or near-

A burning LPG < accidents with LPG on the railways. However, tanker on its side a near-accident with LPG occurred recently on near Eindhoven the road, near Eindhoven. An LPG tanker turned prompted evacuation of over and caught fire. This could have been fol- the motorway lowed by a large explosion, known as a BLEVE over a radius of (Boiling Liquid Expanding Vapour Explosion). 300 m [Spits] The fire brigade had to extinguish the fire from a distance of 300 m to 400 m using a crash tender [Spits, 15-07-2003], as a BLEVE can produce a fireball with a diameter of 300 m. The risk of a BLEVE is small because of the design of the tank, which has double walls and is fitted with overpressure valves. There are cold BLEVE’s and warm BLEVE’s, each with different effects [V&W, 2006]. No BLEVE has occurred in the Netherlands so far, but there have been examples in America, Spain and recently in Greece. As early as 1978, the Dutch Ministry of the Interior summarised statistics from outside the Netherlands in a report, together with a description of the phenomenon [Toneman, et al., 1978].

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A burning train killed 320 people in Iran on 19 February 2004 when a tank wagon exploded The results of a [Planet.nl, 2004]. The train was composed of 51 wagons, including wagons carrying petrol, fireworks factory explosion in sulphur, cotton and artificial fertiliser. Such hazards are also present on the Dutch railway Enschede, system, where hazardous chemicals include chloride. Fortunately, there have so far been no May 2002 major accidents involving such goods in the Netherlands. [Jörgeb Caris] < < Although major disasters with a large number of victims are rare in the Netherlands, they do The results of an occur. One example of a disaster involving infrastructure was when a cargo aircraft crashed aircraft hitting into the Bijlmer district of Amsterdam in October 1992, hitting a large multi-storey building, kill- a multi-storey ing 43 people and injuring 45 [NBDC, 2003]. Another was when a fireworks factory exploded building in the Bijlmer, October in Enschede in May 2000 causing 21 deaths, injuring 945 people and provoking public uproar 1992 [WWP [NBDC, 2003]. The after-effects in particular illustrate the public consequences of disasters Diemen] with large numbers of victims. Disasters of this scale can also occur on the railway. Obviously, the effects of such an incident in a densely-populated inner-city area are several orders of magnitude more serious than if the same disaster were to strike a thinly-populated area.

7.1.3 Social safety Besides the issue of physical safety, there < Crime at the is that of ‘social safety’ – crime prevention. station: ‘La gare’ Social safety has subjective and objective [Fritz Gerlach, 1965] components and has to do with the well-being of people. It encompasses actually being safe (objective) and feeling safe (subjective). The impact on crime of buildings over infrastructure is not the same as that of buildings beside the infrastructure. Building over infrastructure creates a new underground space and crime in underground spaces has been the object of some research [Durmisevic, 2002].

When construction takes place close to railway infrastructure, a narrow strip of land is generally kept free because of environmental regulations. If the dimensions of this strip are

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poorly chosen, the resulting zone attracts crime and is difficult to manage. People ‘hanging around’ in such areas is a common problem at and near stations. Stations require manageable spaces and effective functional routings. It is also important to consider semi-public spaces such as shopping areas.

Attention to social safety is also required during the construction stage; the building process may create temporary situations that encourage crime, such as solid barriers that obscure lines of sight. It is preferable to leave the construction process visible to passengers, giving a better overview of the surroundings.

7.2 Approaches to physical safety

There are two possible approaches to physical safety. The first is the probabilistic approach, in which the probability of an accident is calculated, together with its consequences. The second is the deterministic approach, which involves drawing up various accident scenarios and identifying ways of minimising their consequences. This section will discuss both methods briefly.

7.2.1 The probabilistic approach to safety This approach calculates risk by multiplying the probability of an accident by its consequences. The result of this calculation is a risk level, which must be lower than the socially accepted level of risk. Probabilistic risk analysis can be either qualitative or quantitative. The first step is to identify possible accidents. Then, we estimate the probability of each accident and the severity of its consequences. Within this estimate each accident can have different consequences, each with their own probability. One use of probabilistic risk analysis is to calculate risk contours around installations and linear infrastructure.

y y

IR = 10 - 7

IR = 10 - 6

Two-dimensional < x x risk contours IR = 10 - 6 around IR = 10 - 6 installations IR = 10 - 7 and linear IR = 10 - 7 infrastructure calculated using Installation Line infrastructure a probabilistic risk approach 7.2.2 The deterministic approach to safety The deterministic approach looks at the consequences an accident will have if it occurs. The emphasis is not on risk calculation, but on the manageability of the possible accident. Once a fire has started in a tunnel or something has exploded under a viaduct, the important thing is to take effective measures to control the incident. Emergency services, such as the fire

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brigade and the police, only deal with the consequences of accidents, not with the probability of their occurrence. However, it is difficult for the emergency services to prepare for certain types of accident, as little is known about their effects and there are no appropriate historical references [Ale, 2003].

7.2.3 The safety chain To achieve integral safety, we must take measures at different levels and scales. Different parties are responsible for integral safety at different points along the safety chain. • Pro-action: eliminating structural causes of danger • Prevention: eliminating direct causes of danger • Preparation: being ready for action if an incident occurs • Repression: taking countermeasures and providing assistance during an incident • Follow-up: restoring the situation to normal as soon as possible after an incident

Pro-action Prevention Preparation Repression Follow-up < The safety chain

Risk management Crisis management After-care

The parties involved in the design of new buildings over and near the railway are mainly responsible for the pro-action and prevention stages. They can enhance physical safety by designing premises in such a way that they can be used in as safe a manner as possible. Organisations like the fire brigade are mainly responsible for safety once the building enters service. Fire safety is of course included in the design requirements of the Bouwbesluit. A current trend in the development of these projects is to involve the fire brigade earlier in the process, to benefit from their experience of dealing with incidents. Involving the fire brigade at an early stage can generate support for designing safety into the building and acceptance of safety measures. It also encourages designers to pay more attention to preparation and repression measures.

7.2.4 The ALARP principle Generally speaking, buildings over and near the railway are so designed that they will obtain planning permission. A designer can go beyond mere compliance with statutory regulations to provide a level of safety higher than that which is strictly necessary. However, the more measures are taken to enhance safety, the higher the costs will be. The ALARP principle can help determine whether extra safety measures are required. ALARP stands for As Low As Reasonably Practicable, the idea being that if it is possible, at a reasonable cost, to achieve a level of safety higher than that required by regulations, then one must do so. The extra costs of measures and their contribution to a higher safety level are compared to determine what is ‘reasonable.’ Cost and benefit must be logically linked.

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7.2.5 Comparison between Dutch and foreign regulations If one looks only at safety regulations, it would appear to be easier to develop property over railway tracks in other countries. The major difference is that hazardous goods are transported through many Dutch stations where property development close to and over the railway tracks is considered. The issue does not arise at the terminus stations of Paris or London, as inner-city termini are not a logical destination for hazardous goods. Nor, for instance, do hazardous goods pass through the Lehrter Bahnhof in Berlin (a cross station).

A second difference between Dutch and foreign practice is that there is more focus on effect range in other countries and more focus on the distance of calculated risk contours in the Netherlands. If effect range is used, the maximum distance at which an accident can cause victims is taken as a contour for new building. This ensures that there will be no victims in the vicinity should an accident occur. In the densely-populated Netherlands, only building outside the effect range is not possible, as this would take up too much space. The railway network is such that it is not possible to re-route hazardous goods around cities. Completely new lines would be needed, which would be impossible on either spatial or financial grounds. Taking account of the probability and effects of accidents was therefore a precondition to the development of zoning policy in the Netherlands [Ale, 2003].

7.3 Rules and regulations

As developing property near the railway is not yet very common, there are only limited regulations in this area. In this section, we shall examine those rules and regulations that do exist in the Netherlands. These consist of the Railway Act and the regulations derived from it, promulgated by ProRail, the Dutch railway network manager. Then there are regulations concerning internal and external safety. Finally, there are regulations for the buildings themselves. As we indicated above, the situation outside the Netherlands differs substantially, so we shall only discuss Dutch regulations.

7.3.1 The Railway Act The Spoorwegwet (railway act) is the statutory instrument on which regulations for construction near railway tracks are based. Articles 19 and 20 are of particular interest.

Article 19 concerns the safe and appropriate use of the railway network and the government’s financial interest in its use, management and maintenance. The article indicates that it is the Minister of Public Works who authorises the use of railway land for non-railway purposes. Restrictions can be imposed when planning permission is granted for land near railway tracks.

Article 20 concerns the physical boundaries of the land discussed in Article 19. Article 20 indicates that building is possible at a minimum distance of 11 m from the centre of the nearest track. Depending on the quality of the soil, this distance may be greater, as foundations for new structures could affect the track substructure. The possibility does exist of building within 11 m of the nearest track centre, but applicants have to demonstrate a need. The basic criterion in deciding how to apply the law is the aim of achieving optimum urban density around stations.

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Building within 11 m of the nearest track centre requires a permit from the Minister of Public Works. Railway network manager ProRail acts on behalf of the Minister in this instance and their requirements are as follows: • The applicant must demonstrate that it is possible to manage the risks involved. • The applicant must cover any extra costs that might arise, both during construction and during maintenance by ProRail. • There must be no disruption to railway operations during construction. • The new structures must not impose any limitations on the use of the railway infrastructure, such as lower speed limits at stations or restrictions on the use of specific tracks for the transport of certain goods. • The new structures must not limit ProRail’s own activities in any way.

7.3.2 Design regulations concerning railway infrastructure Plans for building over and near railway tracks are checked against the Ontwerpvoor- schriften Spoorwegverkeer (OVS, railway design regulations) [Railinfrabeheer, 2001]. When new structures are to be built within 11 m of the nearest track centre, measures must be taken to limit the risk and consequences of train collisions. The design of platforms is based on regulations in the OVS concerning the basisstation (basic station) in general and platforms in particular [Railned, 1999]. The regulations require that, to reduce the risk of train collisions, derailment guards be placed between or beside the tracks, sand embankments be built or other measures be taken, of which the effectiveness is to be demonstrated by the structural engineer. The regulations contain no specific requirements concerning structures over the track.

7.3.3 Regulations concerning external safety By ‘external safety’ we mean the risks that the use of railway infrastructure poses to the surroundings. In particular, we are thinking here about the risks to the direct surroundings when something goes wrong in the production, handling or transport of hazardous goods. Exter- nal safety excludes the safety of users of the infrastructure itself. Risk regulations do not constitute a statutory criterion under the Town and Country Planning Act. However, when a zoning plan is established, local authorities must take account of risk contours related to the transport of hazardous goods. Regulations and generally accepted computer models derived from these regulations are based on only two dimensions and take no account of vertical position.

Risk levels are calculated by considering the types of hazardous goods transported, the speed at which they are transported, those variables of the infrastructure that affect safety, the function of the buildings and population density. It is possible to reduce risk by taking measures that diminish the probability of an accident and/or by taking measures that diminish the effects of possible accidents. At the source, it is possible to take measures with respect to track layout and train speed, and by transporting smaller quantities of hazardous goods. In the case of existing and planned infrastructure, however, these variables are usually fixed, with the quantity of goods determined by fixed forecasts. If it is not possible to change the infrastructure, the only way to reduce the risks is to change the urban environment: demolish existing buildings and build elsewhere.

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We distinguish between two types of risk in external safety: individual and societal. Individual risk is the probability that an individual will die if he or she stays next to a given transport route continuously, without protection, for one year. This probability is determined by the type of infrastructure and the quantity and type of hazardous goods that are transported. It is not influenced by the size of the population or by shielding from neighbouring buildings. The criterion for acceptability of individual or localised risk is usually depicted as contours on a two-dimensional map [Ale, 1996 & Suddle et al., 2002]. The norm for individual risk is 10 -6 per year, i.e. one unprotected individual in the vicinity of the railway would die in a million years. The construction of buildings with vulnerable functions is prohibited within this contour. By ‘vulnerable functions’ we here mean dwellings, offices with more than 50 employees, hospitals and schools. Existing buildings need only be demolished where the risk is greater than 10 -5, i.e. a probability of once in a hundred thousand years.

Societal risk is the probability that a group of individuals will die at the same time as the result of an accident involving hazardous goods. The norm for societal risk, for a disaster with N deaths is:

2 SR(N) = ƒN * N where ƒN is the probability of the accident and N is the number of deaths.

The basic idea behind this norm is that the probability and the size of the accident are not exchangeable. A low probability of a major accident is considered more serious than a high probability of a minor accident. This societal risk is not codified in legal norms, but there is a reference value that forms the basis for approving new building projects. Because this is a reference value, competent a uthorities may deviate from it if necessary. An accident with 10 victims must not occur more than once in ten thousand years (10 -4) and an accident with 100 victims must not occur more than once in a million years (10 -6), i.e. 100 times less often.

1.00E-00

Societal risk < 1.00E-01 calculated for Large fire / firework factory / the transport of Derailment / fire aircraft Highly toxic gasses / BLEVE hazardous goods 1.00E-02 (both axes logarithmic) 1.00E-03

1.00E-04

Calculated risk (example) Reference value 1.00E-05

1.00E-06 Frequency of more than N casualties per year 1.00E-07

1.00E-08 1 10 100 1 000 Number of casualties (N)

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7.3.4 Regulations concerning internal safety Internal safety is the safety of people using the transport system. When railway tracks are built over, this affects passengers involved in an accident under the new structure. There is already much research on internal safety in tunnels available, so we shall not discuss this further here. For the railway system, there is virtually no difference between an accident in a tunnel and an accident under a large overhead structure. Regulations concerning tunnel safety already exist or are in preparation. These mainly concern escape routes and smoke emission in case of fire.

7.3.5 Regulations concerning buildings The most important regulations related to fire safety are contained in three acts: the Woningwet (housing act), the Wet Milieubeheer (environmental act) and the Arbeidsom- standighedenwet (working conditions act) [Langeweg, 2003]. The Wet Milieubeheer is intended to prevent danger, damage and nuisance to the surroundings. Where there are risks, an environmental permit must be obtained. The fire regulations in the Wet Milieube- heer focus on limiting the effects of a fire on its surroundings and not on the fire resistance of the building itself. The Arbeidsomstandighedenwet focuses on the health, safety and well- being of staff. It covers such matters as the safety precautions that must be taken and the provisions that must be made for emergencies. The health and safety inspector can forbid the use of a building on the basis of the Arbeidsomstandighedenwet, but he cannot force structural changes. However, this is possible on the basis of the Woningwet, which contains the most important building regulations. Fire safety requirements are contained in the Bouwbesluit (building decree) which is based on the Woningwet.

Buildings must comply with the Bouwbesluit, which formulates structural requirements in the form of performance requirements. However, it is not quite clear on what these requirements are based. This is apparent when we compare the requirements of different European countries. Every country has its own requirements, which are generally based on national perceptions, history, experience, lessons learned from fires and expert opinions. Although general opinions on fire safety are similar across Europe, there are major differences in the specific requirements [Langeweg, 2003]. Obviously, the Bouwbesluit cannot regulate the safety of a building for all scenarios. It simply contains requirements for the safety of persons when a fire occurs in the building. The Bouwbesluit takes no account of the presence of a railway track under the building, the transport of hazardous goods or train fires.

7.4 Elements of risk analyses

To comply with regulations on external safety, the level of safety must be shown to be sufficiently high. Qualitative and quantitative risk analyses are used to determine what accidents can occur and what effect they could have when buildings are constructed over and near the track. These risk analyses have input parameters. The present section will discuss the input parameters that form the basis of a risk analysis for new building over or near railway infrastructure.

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7.4.1 Types of accident that can occur on railway infrastructure There are four possible types of accident on the railway: derailment, fire, explosion and leakage of toxic gasses. These accidents can of course result from one another, e.g. a derailed train can catch fire. For the purposes of the present discussion, ‘derailment’ means any type of mechanical failure, including a collision between trains. This category also includes the secondary consequences of accidents, such as a derailed train that ends up on another track. Derailments or collisions can also lead to fires, but these consequences will be included in the risk analysis of fire. Besides collisions and derailments, accidents can also occur when a train loses its cargo. The effect range of derailment is about 30 m.

Fires can start on the railway infrastructure and in buildings close to and above it. Either situation can pose a risk to railway passengers and to the occupants of the buildings. Fires can also spread from the infrastructure to the buildings or vice versa. In risk analyses, a distinction is made between fires involving solids and those involving liquids and gasses. Solids burn where they ignite, whereas liquids and gasses can spread out over a large area. If the track is on an embankment, liquids can run down the embankment and affect an even larger area. The effect range of fires is also about 30 m, but can be greater in the case of a pool fire involving liquids.

Railway transport includes the transport of hazardous goods that can explode. An accident involving explosive materials is the third category of accident within this research. One explosive material frequently transported over Dutch railway lines is LPG. A tank of LPG can cause a BLEVE, which has an effect range of 100 m to 300 m. A BLEVE can also occur with substances other than LPG.

The fourth and last type of accident we shall consider is leakage of toxic liquids and gasses. Toxic liquids will have virtually no influence on buildings and structures over or near the track. However, liquids – especially gasses – can cause a large number of victims. A toxic cloud can spread over several kilometres. A distinction is made between gasses that are lighter than air and those that are heavier than air, as they spread differently. Toxic substances have an effect range of a few kilometres.

7.4.2 Accidents on tracks at different vertical positions In Chapter 3, we defined four different vertical track positions. The distinction between these vertical positions is important for risk analysis, as they influence the effect ranges of accidents.

Vertical track < Underground Subsurface Ground level Elevated positions

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• Underground tracks have the advantage that there is limited interaction between internal and external. Derailments and fires on underground tracks have less effect on buildings above. The walls of the tunnel act as derailment guards, and liquids only spread over the bottom of the tunnel, making them more manageable. However, the risks for train passengers are higher. • Subsurface tracks have more interaction with the buildings above and beside them. The buildings are therefore at risk, but the walls along the tracks help to contain accidents. • The analysis of railway tracks at ground level is more complex on account of the possible derailment scenarios. The consequences of derailments are much more complex, e.g. a derailing train can directly collide with a building beside the track. The effect ranges are also larger. • The effects of accidents on elevated tracks will be even more complex. A derailed train can fall down the embankment and liquids can flow from the elevated tracks to, for instance, the station building below, turning an accident into a disaster.

7.4.3 Transport of freight versus transport of persons When conducting risk analyses, it is important to know whether or not the tracks carry freight traffic. If they do not, there is no risk of explosions or accidents involving toxic materials, and the risk of fire is much lower. A fire on a freight train may impose far higher fire loadings on the structure.

Category Example < Categories of A Flammable and very flammable gasses LPG / Propane hazardous goods B2 Toxic gasses Ammonia transported B3 Highly toxic gasses Chloride by train over C3 Very flammable liquids Hexane Dutch railway D3 Toxic liquids Hydrogen sulphide infrastructure D4 Highly toxic liquids Acrylic nitrile

7.4.4 Difference between buildings beside and over the track For risk analyses, there is a huge difference between buildings beside and over the track. The effects of accidents are very different and there are many blind spots in the rules and generally accepted calculation models concerning over-track structures. When building beside the track, it is possible to calculate and draw risk contours along the track and to keep all new construction outside that line. When building over the track, however, it will be necessary to interpret rules and regulations to a greater degree. In other words, the risk analysis for over- track construction contains many more uncertainties. It is possible to prevent derailed trains striking buildings by building derailment guards beside the track, as prescribed in the Dutch Design Regulations for Railways. This has been done near Amersfoort Station. The design regulations do not cover structures over railways, but there are practical examples that can serve as references, such as Rijswijk Station where columns for an overhead artificial ground level are mounted on derailment guards.

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Derailment guard beside the Eempolis office

complex near Amersfoort < Station

Columns on < derailment guards between the tracks at Rijswijk Station

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One difference between covering railway tracks and building next to them is that if the tracks are covered, smoke cannot escape and the situation becomes dangerous more quickly. This has direct consequences for internal safety. It is also more difficult to react to the incident; fire fighting is more difficult. Creating an enclosed space also brings the risk of creating the conditions in which an explosive mixture of gasses can form. On the other hand, enclosing toxic gasses may enhance external safety, as the gas will spread less and there will be fewer victims. In planning over-track construction, beside the costs, one must balance internal and external safety. What is safer for those outside may be more dangerous for railway passengers and vice versa. A train collision or fire could bring a whole building down. Apart from the victims and the loss of the building itself, this could bring the whole railway system to a standstill, with dramatic economic consequences.

7.4.5 The risks that buildings pose to railway infrastructure Accidents can also take place within a building that influence the railway infrastructure next to or under it. Parts of a building can fall down, or people can throw objects onto the track that interfere with trains. Fire can also lead to collapse of all or part of a building. These scenarios must be taken into account and it is possible to design in such a way that such accidents are made less likely. Finally, explosions can occur in the building and can influence the railway system. Disruption of the railway system can easily have major economic consequences.

7.4.6 Safety during construction versus safety in service For risk analyses, we must distinguish between the construction phase and the service phase. Building maintenance is similar to construction, as work is carried out on the building during both. Broadly speaking, hazards during the service phase are caused by the railway infrastructure and hazards during the construction phase are caused by the risks inherent to construction work on the building. To ensure a satisfactory level of safety, both for construction workers and for people in the vicinity, safety should be part of the specifications, for which the client is responsible [Meijer, et al., 2001].

Various accidents can occur during the construction of buildings close to or over the track. Construction materials can fall and cause damage, or fires can start. These accidents can also cause consequential loss, even including collapse of the entire structure [Suddle, 2001]. Steps must be taken to prevent building materials or construction equipment falling onto the railway infrastructure, especially when it is in service. Tracks can be taken out of service dur- < Crash deck ing specific hoisting procedures and re-opened to protect the motorway from when construction activities are under way falling building that do not involve risks to the railway. It is also materials during possible to construct a crash deck over the construction over infrastructure that prevents smaller items fall- the A10 West motorway in ing onto it. This crash deck can be temporary Amsterdam or permanent. A crash deck was used for the Haagse Poort over the Utrechtsebaan motorway in The Hague and during construction over the A10 West motorway in Amsterdam.

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Construction activities can cause secondary damage, e.g. the track could settle, which could cause a derailment. The construction process can also damage railway systems because of the vibration that occurs during construction. This is a point to bear in mind whenever building close to or over railways, because construction work must not interfere with the use of the infrastructure.

7.5 Recent developments in physical safety

Recent public attention to physical safety has prompted extensive research and new initiatives to improve safety. Publications of interest in the field of safety policy include the reports Verantwoorde risico’s, veilige ruimte (sound risks, safe space) from the councils of the Minis- tries of Urban Planning and Public Works and Nuchter omgaan met risico’s (Coping sensibly with risk) from the Dutch National Institute for Public Health and the Environment (RIVM) [VROM and V&W, 2003; RIVM, 2003]. In addition, there is a trend towards requiring safety impact statements in addition to the existing environmental impact statements, and there have been specific developments in railway safety. We shall discuss these aspects in more detail below.

7.5.1 The advisory councils of the Ministries of Urban Planning and Public Works The problematic nature of urban densification and the transport of hazardous goods has been taken up by the Advisory Council of the Ministry of Urban Planning and the Advisory Council of the Ministry of Public Works. They have drawn up a report containing directives for dealing with external safety. The report identifies three policy domains: chain sources, transport in networks, and safety on location [VROM and V&W, 2003]. ‘Chain sources’ looks at the causes of danger and sources of risk in the context of the chain of activities within which they occur. The second domain is that of the managers of transport networks carrying hazardous goods. Local governments have the lead in domain three, which assesses the risks of urban developments in combination with dangerous activities. The report examines the three domains together.

Three domains < of external safety Domain 1 Domain 3 [VROM en V&W] Chain sources Safety on site

Space and external safety management

Domain 2 Transport and networks

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The report sets out directions for future policy at the various levels at which the problems need to be solved. Cooperation between ministries is an important step in the development of new policy and new regulations. A recent development is that central government is looking at external safety in a more comprehensive fashion, and searching for solutions at the right scale. However, one drawback of the report is that it only gives directions for policy, not practical solutions. It does not provide designers with tools for ensuring that their designs comply with regulations. The present study will focus on domain three, measures applicable to safety on location.

7.5.2 The Dutch Institute for Public Health and the Environment Following the report of the Advisory Councils, the Dutch Institute for Public Health and the Environment wrote a report on how to manage the risks of large accidents: ‘Coping sensibly with risk’ [RIVM, 2003]. The report criticises the variety in the level of risk (including risks other than transport) to which people are exposed, advocating that the policy of the 10-6 level be maintained. On the basis of a cost-effectiveness analysis one can then see whether funds invested in risk reduction have been well spent. When guaranteeing a specific safety level becomes unaffordable, politicians can decide to take less expensive measures or to accept specific risks. Something comparable might also be possible for station areas. Coping sensibly with risk can mean that different environmental risks are not all put in the same box, and that differentiation is needed. This differentiation could involve assessing risks with a high probability but minor consequences differently from those with a low probability but severe consequences. A new trend in risk assessment is that the assessment of physical safety is performed in a more sensible and differentiated fashion and the return on investments in safety measures is examined more carefully.

7.5.3 Safety impact statements The safety impact statement (SIS) is a new tool in urban development, derived from the environmental impact statement. These safety impact statements are expected to play a more important role in station area development and might become a compulsory element, as environmental impact statements are now. Safety impact statements could be made compulsory for large-scale redevelopment projects in station areas, at least when transport of hazardous goods is planned. In projects involving multiple and intensive use of space in combination with the transport of hazardous goods, complex situations arise in which small accidents can lead to major hazards. If the safety consequences are considered carefully at an early stage, it is possible to avoid unnecessary dangers. Furthermore, the overall safety level will be substantially higher if physical safety is treated integrally. This integrated approach is also necessary to prevent safety measures in one place having a negative effect on safety elsewhere.

7.5.4 Developments in railway safety Policy focuses on continuous improvements in safety, and improvements to the safety of railway infrastructure include measures to enhance the safety of the transport of hazardous goods. However, current risk analyses do not include the impact of these measures. That approach has been taken to prevent the risks associated with extra building cancelling out any reduction in transport-related risk. Individual increases in safety should fully benefit

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the overall safety level. Examples of improvements expected are better trains, not shunting trains near stations, a catalogue of railway safety measures from ProRail, chain studies for hazardous goods, urban clearance policy from the Ministry of Urban Planning, routing of hazardous goods, etc. These measures will have a medium- and long term, but positive effect.

7.6 HR-3D physical safety concept

In this section, we shall translate information and trends on external safety into a new concept regarding the external safety of buildings over and near the track. This will include inter- preting regulations on noise nuisance to analyse their effect on physical safety. The concept will encompass the third dimension of risk analysis and a distinction between types of accident, their effect ranges, the urban context, and the difference between near and over the track. This HR-3D method was developed early in 2003 as part of an assignment from the Ministry of Housing, Spatial Planning and the Environment. The assignment was to develop tools to combine physical safety and urban development in design measures, with the Drechtsteden as a pilot project.

7.6.1 Principle of source-transmission-recipient The current Dutch two-dimensional risk analysis does not match recent urban developments. The regulations for noise nuisance have been interpreted to develop a more appropriate method. Measures against noise emission involve the source, the transmission path and the recipient. Measures at the source may consist of installing devices to diminish squeal noise, measures along the transmission path include installing noise barriers, and at the recipient we could install a noise-insulating exterior wall. It is possible to take measures at all three points, and the final result must comply with noise regulations.

Regulations regarding external safety can roughly be divided into three steps. The first step consists of rules of thumb; when the transport of hazardous goods is below a certain level, no external safety calculations are required. The second step is the calculation of a two-dimensional risk contour using models such as the generally accepted IPO-RBM model. A complex quantitative risk analysis may constitute a third step.

When the external safety risk contour has been calculated using one of the generally accepted calculation models, the risk contour is an established fact. Measures along the transmission path or at the recipient do not affect the distance of the contour from the track, and measures at the source – other than changing the quantity of goods transported or the train speed – have no substantial effect. Clearly, this is illogical, as taking measures along the transmission path and at the recipient do indeed affect the safety of an individual. In the following paragraphs, we shall discuss elements that should be added to the generally accepted risk models used in practise to calculate a more precise risk level, one that matches the actual situation, before complex quantitative risk models are needed to calculate even more precise risk levels.

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7.6.2 Introducing the third dimension When we build close to and over railway infrastructure, the third dimension – height – will play a more important role in determining the safety level, yet the generally accepted risk calculation models do not include height. Such models do, however, take account of the fourth dimension – time – in that they make a distinction between daytime and night-time use of urban functions. By definition, multiple and intensive use of space involve four dimensions, but there are as yet no generally accepted risk calculation models that take all four into account. It should be possible to take account of the effect that proposed safety measures would have, purely on the basis of expert opinions, without the need for detailed calculations.

7.6.3 Accidents and corresponding effect ranges External safety is represented by one total risk contour at the 10 -6 level. This risk contour corresponds to a whole range of possible accidents and effects. Given the completely different nature of these accidents, it is not very logical to put them all in one risk contour, as they are scarcely comparable. As mentioned in 7.4, there are roughly four different types of accident. The effect range of derailment and fire is about 30 m, that of an explosion is ten times that and the range of toxic gasses is ten times larger again – it may be a number of kilometres. Because of this difference in effect range and the difference between the probability of these accidents, it is incorrect to place them all in one risk contour – usually between 10 m and 30 m. A more differentiated risk analysis can calculate the actual safety level and determine suitable safety measures.

7.6.4 The local urban context Current calculation models for determining external safety take virtually no urban contexts into account. For instance, the vertical position of the track has no effect on the risk contour, yet it obviously affects the effect range of certain accidents. An accident on a subsurface track will have a smaller effect range than a similar accident on an elevated track. Equally erroneously, such mitigating elements as derailment guards, measures to prevent pool fires, or the spatial arrangement of buildings near the track (e.g. high versus low buildings) have hardly any influence on the distance of the risk contour.

7.6.5 Safety beside the track versus safety over the track The common view is that building over the track is more dangerous than building beside it. This view is open to question. In a two-dimensional analysis, building over the tracks does indeed come out as more dangerous – you cannot get closer to the track than above it. But a three dimensional analysis shows that building over the track is not necessarily more dangerous. People in a building over a tunnel with a robust structure, gas detection, sprinkler systems, ventilation provisions and derailment guards are better protected against accidents than people in a normal building close to the track that has no such protection. On the other hand, building over the track is not automatically safer than building beside it. A balanced risk analysis is needed that takes account of different accidents, the probability of their occurring, their effects and the specific contributions of safety measures.

154 Physical safety

7.6.6 IPO-RBM versus HR-3D The above observations have led to the development of the HR-3D method. This is not a risk calculation model, but a way of thinking, intended to develop risk reduction measures. The basis of HR-3D is differentiation between accidents, their effect ranges and urban contexts. Further research may well take account of practical experience to develop a toolbox with official status, like the IPO-RBM model – the generally accepted risk calculation model for

external safety in the Netherlands. < Effect in IPO-RBM A rough Transport axis open field risk contour comparison between the IPO-RBM risk Transport axis Effect types 3D effect HR-3D calculation and reduction risk contour the HR-3D method

The HR-3D method proposes an intermediate step in the risk analysis that takes specific effects and measures into account. The result is a risk contour that leaves more room for alternatives in spatial design. We shall discuss the consequences of the HR-3D method for individual and societal risk below.

7.6.7 Effect of HR-3D on calculation of individual risk Individual risk is the sum of the probabilities of different types of accident that can lead to the death of an individual. The HR-3D method yields effective measures for each effect type, with a corresponding reduction in risk, for a certain type and quantity of transport and a given probability. By taking specific countermeasures against specific accidents, it is possible to reduce individual risk, possibly from above 10-6 to below that level.

Reduction in individual risk by using 3D risk assessment

"Unsafe"

Toxic < 10-6 substances Specific reduction in individual risk for different accidents

Explosion / BLEVE "Safe" Toxic substances

Fire

Explosion / BLEVE

Derailment Fire

Derailmant

155 Rail Estate

The probability that some kind of accident will occur is calculated by summing the probabilities of the individual types of accident. For each type of accident, we can take measures to reduce the risks in three dimensions. For derailment and fire, we can take measures that substantially reduce the risk. This is more difficult in the case of explosion and toxic gas, but together the measures can reduce the risk to below the 10-6 level, whereas it was initially above that level at the same distance from the track.

On the basis of the above, the individual risk calculation has also been examined in detail, to determine the influence on risk of the distance from the track. The cross section shows a 10-6 contour at 20 m, a 10-7 contour at 200 m and a 10-8 contour at 500 m. According to the regulations concerning individual risk, no vulnerable object may be sited less than 20 m from the track. The level of individual risk is not calculated for distances closer than 10 m from the track, as it would be too inaccurate. There is a high degree of variation in individual risk close to the railway infrastructure. This is of course logical, as the relationship between risk and distance is logarithmic. The individual risk contour is estimated using a negative exponential curve fitting method.

120 Individual risk -6 < 100 calculated for distances of 10 m to 500 m 80

20 Curve-fitting Individual risk as a percentage of 10

Basic input 0 0 50 100 150 200 250 300 350 400 450 500

Distance from the centre of the transport axis [m]

Individual risk contours for line infrastructure play a role at a distance of 10 m to 30 m. With the help of the same curve-fitting technique, individual risk has also been estimated for distances of 10 m to 30 m from the railway infrastructure. The risk is estimated for 19 m compared to 20 m and for 10 m compared to 20 m. The variation in individual risk over 1 m turns out to be only 0.8%. Obviously, this risk calculation applies to an average situation. Other situations may have a different distribution of risk types and involve different types of hazardous goods, but this general situation gives an interesting estimate of the risk variation within such risk calculations. The variation in risk between 20 m and 10 m is also very small; 8.3%. The IPO-RBM risk model normally used to calculate individual risk itself has an overall inaccuracy of more than 10%, because of inaccuracies at the intermediate steps. This overall inaccuracy is unrelated to the inaccuracies that arise because of the limited availability of accurate statistics – those inaccuracies are much larger. Given the results of the above estimate, it is therefore debatable whether using this individual risk contour for line infrastructure is useful and appropriate at such distances from the railway tracks.

156 Physical safety

120 The difference in < -6 108,3% 100,0% individual risk at 100 100,8% 10 m and 30 m 99,2% 92,3% from the track 80

20 Individual risk as a percentage of 10 0 0 5 10 15 20 25 30 Distance from the centre of the transport axis [m]

7.6.8 Effect of HR-3D on calculation of societal risk The HR-3D method has less effect on calculations of societal risk. Risks of derailment and fire are manageable, but have only a limited effect range and the groups at risk are smaller. Explosions and toxic gasses affect a larger area and one incident can produce a larger number of victims. The nature of such accidents means that a substantial reduction (i.e. a factor of between 10 and 100) for the total area around the line infrastructure is impossible in economic terms. It is only possible to reduce a limited part of the risk. Policy makers must choose between restricting urban planning near line infrastructure, reducing risks at the source (introducing even safer forms of transport or stopping the transport of hazardous goods altogether), or accepting the societal risk inherent to a combination of urban planning around stations and the need to transport hazardous goods.

7.6.9 Considering design and policy Merely calculating physical safety is not enough. Absolute safety is impossible to achieve, as there will always be certain risks that cannot be managed. As a result, specific investments in safety measures are required, and this needs to be considered at the correct scale level. It is difficult to find affordable, effective measures that will substantially reduce the probability of certain types of accident. Some risks can be reduced by measures taken within a building project, while reducing others requires policy at an urban level. Generally speaking, it is virtually impossible to reduce the risk of accident types with a large effect range within a building project; one must either address them at a higher level of scale or else accept them. By contrast, measures at project level can have an impact on accidents with a limited effect range. The figure below illustrates the confrontation between spatial design and safety at different levels of scale. The effect ranges of different accidents are indicated in the middle of the figure.

The way the HR-3D method deals with physical safety can be placed in the same framework as the report ‘Coping sensibly with risk,’ published by the Dutch National Institute for Public Health and the Environment [RIVM, 2003]. When developing station areas it is important to make practical investments in safety measures. It is possible to incorporate measures against derailment and fire cost effectively, whereas measures against explosions and toxic gasses are limited in their effects and very expensive. Furthermore, measures to manage

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Spatial design Physical safety < The HR-3D method: Urban ambition Safety level ambition confrontation Functional programme Transport systems between safety and spatial design Infrastructure Infrastructure layout Return on investment Confrontation

Benefits from policy s

y Masterplan Transport y 1 000 m Cit Cit Policy plan axes Measures outside project boundarie

300 m

Zoning plan Spatial 100 m Traffic plan arrangement Image quality plan Density District Layout plan District

30 m

PR 10-6 s n

Building plan Building 10 m Layout plan specifications Building Building Effect distance project boundarie Measures withi Derailment Fire BLEVE / Explosions Toxic substances 3 m Benefits from measures Solutions

the risk of explosion usually result in over-dimensioned structures, the size of which could encourage crime and reduce spatial quality. Such measures might make a contribution to physical safety, but they also transform projects involving intensive and multiple use of space into unpleasant spaces.

When planning the development of station areas, we can consider three scenarios regarding the transport of hazardous goods: stopping it altogether, not building or accepting unman- ageable hazards with a very low probability. The last scenario could be appropriate where building in station areas is really necessary due to a qualitative and quantitative lack of space coupled with an absence of economically attractive alternatives to the transport of hazardous goods by rail. In any case, it is impossible to achieve absolute safety. Policy should focus on stopping the transport of hazardous goods long term, but it is worth considering accepting a certain level of danger until this is achieved, as urban development will continue.

158 Physical safety

7.7 Reference projects

The HR-3D method has been used on three real-life reference projects, and in this section we shall look at the results. The projects are at different levels of scale: the Piazza Center in Eindhoven (a single building), railway land in Dordrecht (an urban district) and the Amsterdam Zuidas (a large urban district).

7.7.1 Piazza Center, Eindhoven

The Piazza < The original Piazza Center was built in the Center, a 1960s 1960s. By the 1990s, this shopping centre development no longer complied with modern requirements located close to a railway line and a choice had to be made between demoli- tion and renovation. The choice was made to renovate the building and to extend it towards the railway. However, the Piazza was already very close to the track, which carries hazardous goods. A discussion ensued regarding the external safety of the building, which did not comply with the regulations on individual risk, as it is too close to the track. The external wall is about 5 m from the centre of the nearest track, whereas the risk contour for individual risk is 15 m from that line.

Early in December 2003, the Minister of Urban Planning threatened to stop work on the project [Eindhovens Dagblad, 2003]. This prompted the City of Eindhoven to look for targeted measures to reduce the risk, in a taskforce involving the ministries of Urban Planning and Public Works. Holland Railconsult (now Movares) advised this taskforce. Demolishing the Piazza Center was not an option, but it could not open until the problem was solved. The societal risk is higher than the reference value, but this had already been accepted. Societal risk had been left out of the discussion.

Given the quantity of hazardous goods that were being transported, the only way of com- plying with regulations and reducing the risk contour was to impose a 40 km/h speed restriction. At considerable expense, the railway sidings had recently been modified to make speeds of 60 km/h possible and hence increase the capacity of the railway network. A speed restriction of 40 km/h would have reduced capacity and would have constituted a disinvest- ment. It was also claimed that the quantity of hazardous goods would diminish when the Betuweroute (the dedicated freight line from Rotterdam into Germany) comes into service in 2007, but even after that date a large quantity of hazardous goods is expected to pass through Eindhoven.

The project was also used to test the HR-3D method. To renovate a building like the Piazza Center in such a way that it complied with legal requirements, it had to be proven that an individual would not die as the result of an accident on the railway infrastructure more often

159 Rail Estate <

than once in a million years. This is possible even without a suitable computer model. To The Piazza Center, prove that the building complies with regulations concerning individual risk, the risk contour close to the track that is calculated by existing computer models is assumed to be ‘safe’, i.e. a risk below the -6 < < 10 limit. This being so, we may assume that a death will occur in an unprotected building The shopping just outside this risk contour less than once in a million years. Using the HR-3D method, we centre is only a few can then determine how the risk increases when this standard building is moved towards metres from the railway infrastructure, i.e. to inside the risk contour. Specific measures can be designed the railway to compensate for the extra risk. The point is that the HR-3D method takes account of measures that existing computer models – wrongly – ignore.

If an accident involving toxic gas occurs, the effects in a building 15 m from the track will be virtually the same as those in a building 25 m away. Toxic gasses can spread over kilometres, so moving the building a few meters towards the track will not have a substantial influence. Protection against toxic gas accidents depends on the exterior wall and the air conditioning installation. The situation with regard to a BLEVE is similar, as such an accident can produce a fireball 300 m in diameter. However, the risks are different for fire and derailment. A distance of 15 m is substantially safer than a distance of 5 m for these types of accident and extra measures should be taken to provide protection. This is possible, and the measures are very cost-effective. Two very effective measures for railway infrastructure are derailment guards and liquid drainage to prevent pool fires [Wilde, 2004].

Derailment guards can be built quickly, easily and for a limited cost. Such guards are needed to achieve compliance with Dutch railway design rules. They also limit the secondary effects of a derailed train. Derailment guards can be installed between and outside the tracks. In the case of the Piazza Center, they were placed outside, as this meant they could also act as a buffer for flowing flammable liquids. It was possible to limit the risk of a pool fire by using the ballast bedding for drainage. If the permeability of the ballast bedding is insufficient, a drainage system can be added. These measures make it possible to construct a building closer to the track while maintaining or even increasing the safety level. For Eindhoven, this has meant that a zone 10 m either side of the railway infrastructure is now available for urban planning. Points that required extra attention at the Piazza Center were the attack routes for the fire brigade (including those for the railway infrastructure), the maintenance of the façade, extra fire protection behind the façade and the evacuation plan for the shopping centre.

160 Introduction <

The railway land 7.7.2 Railway land at Dordrecht at Dordrecht, as Urban development and railway infrastructure conflict when hazardous goods are transit looks now ported. The Ministry of Urban Development, Housing and the Environment asked Holland Railconsult to draw together the available knowledge on these subjects and to identify opportunities for urban development that could arise from acting within the spirit of existing rules and regulations regarding external safety. Urban development was to focus on the possibilities of multiple and intensive use of space on railway land at Dordrecht. This research was undertaken by a team, consisting of the cities of Dordrecht and Zwijndrecht, the Province of Zuid-Holland and the Ministry itself [Wilde, et al., 2003]. The railway land in Dordrecht was chosen because it is one of the biggest bottlenecks in the Netherlands, both for urban A proposal development and for the transport of hazardous goods. In addition, the study could relate to for urban ongoing research in this area. development, from the workshops The Ministry of Housing, Spatial Planning and the Environment has set up a special director- related to research for the Ministry of ate on external safety to develop policy and measures in this area. One of the directorate’s Housing, Spatial tasks is to map the interests of urban development. To enhance the quality of urban plan- Planning and the ning, the directorate weighs up conflicting claims on space. The Directorate General of

Environment < < < Spatial Planning supplies the building blocks for a national policy, and the HR-3D method that resulted from the assignment in Drechtstede became one of these building blocks.

The railway land at Dordrecht, It was found that safety regulations are taken as a given framework, into which urban develop- from above ment has to fit. Even if there are only vague data on risk sources, they are taken into account <

161 Rail Estate

implicitly in the planning process. External safety enjoys a protected status and this has generally been accepted. Claiming external safety conditions as a given fact puts designers at a disadvantage. When a conflict arises between urban planning and the transport of hazardous goods, it is always urban planning that has to find a solution. Furthermore, the regulations have been found not to take into account the real contribution these solutions make to the level of physical safety. As a result, one fails to attain the ultimate goal of urban planning – if it is not possible to achieve spatial quality what is the use of urban development?

It would facilitate urban development in the vicinity of stations if planning were to start with a statement of what is being aimed at and then seek confrontation with external safety. In this confrontation, discussion should centre not on the spatial concessions required to comply with regulations on external safety, but on how the regulations can be used to provide the urban quality that is aimed for. Urban planners and architects should have more tools for dealing with their design as it affects external safety, so that they can attain the goal of pro- ducing a quality urban environment.

For the research on railway land at Dordrecht, the decision was taken to first produce an urban plan that took no account of external safety. Subsequently, measures were designed that would make this proposed urban plan possible. The HR-3D method turns part of the design process around by giving priority to spatial quality, creating more liberty for urban design. In the case of Dordrecht, the urban design was not taken further, but the HR-3D method showed that there are more options for urban development. This is mainly because urban development is planned closer to the track, as a result of which less urban space remains unused. It has not been proved that more square metres could be developed in exchange for this level of societal risk. However, taking specific safety measures on the infrastructure can reduce the risk of an accident or a disaster, thereby reducing societal risk.

7.7.3 Zuidas, Amsterdam For Amsterdam Zuidas, the external safety of the Dike Model and the Dock Model were compared. In the Dike Model, the infrastructure is added to the existing railway embankment and only the land beside the embankment is developed. In the Dock Model, the infrastructure is also expanded, but it will be placed underground in tunnels to allow the development of a million square metres of property overhead. The elevated infrastructure and the underground infrastructure, combined with the larger amount of building planned, have different consequences for the safety level, both internal and external.

Existing safety analyses could prompt the conclusion that neither Dike nor Dock comply with existing regulations concerning physical safety. By these standards, both variants are unsafe, with the Dock Model being less safe than the Dike Model [Projectgroep Veiligheid Infrastructuur Zuidas, 2003]. Both models are unsafe in terms of the societal risk resulting from the transport of hazardous goods, both by motorway and by railway. The Dock variant is three times more hazardous than the reference value for societal risk. However, one needs to take into account that twice as much property is planned for the Dock variant as for the Dike variant and that there will be more inhabitants. Nevertheless, the Dike exceeds the levels in the standard by a factor of 61, the Dock by a factor of 198. Both variants are far outside the limits.

162 <

Birds eye view The problem arises almost exclusively from the planned transport of LPG. If we eliminate of the Zuidas this, both variants comply with the regulations concerning external safety. The risk contour Dike Model

for individual risk has no consequences for the Dike Model, as in this variant the buildings

[dRO Amsterdam] < < < would be far enough away. In the Dock Model, building would also take place over the railway infrastructure, placing it within the contour for individual risk. Birds eye view of the Zuidas Dock Model Holland Railconsult gave a second opinion on the Zuidas, based on the HR-3D method. The [dRO Amsterdam] fact that the entire population of the Dock Model is projected at ground level, at very high density, makes the societal risk extremely high. However, the actual situation differs substantially from what the available computer models calculate, and it pays to introduce a more differentiated perspective regarding the actual safety level. For instance, if a 100 m high building over the infrastructure does not collapse as a result of a disaster, the occupants from a certain number of floors upwards will be safe from most types of disaster. This means that a large part of the population can be left out of societal risk calculations, for certain disasters. Only toxic gasses lighter than air might be a problem. The distribution of a fire in the tunnels also requires a more detailed assessment.

The Zuidas project shows that the HR-3D method can have advantages not only when calculating individual risk, as in the case of the Piazza Center, but also with respect to societal risk. In particular, the presence of high-rise buildings (up to 100 m) makes a difference to the calculation of societal risk. As well as differentiating between types of accident, the model also allows us to take account of the number of inhabitants. It is possible to develop more property than with standard risk calculations, while guaranteeing the same level of safety.

7.8 Conclusion

Physical safety is one of the most important challenges for development over and near railways. The problem arises primarily from the transport of hazardous goods through many Dutch stations, and from incomplete and unclear rules and regulations. Although railway infrastructure is very safe, accidents involving a large number of victims are possible. Public aversion to accidents with a large number of victims means that safety levels have to be very high.

163 Rail Estate

Two types of risk assessment are used to determine safety levels. On the one hand there are probabilistic risk analyses, which involve assessing the probabilities and consequences of accidents. The product of the two is compared with socially accepted risk levels. On the other, there are deterministic risk analyses, in which the effects of possible accidents are determined and measures are designed to manage these risks.

When building over railway infrastructure, three risk analyses are needed for external safety: an analysis of the risks that railway infrastructure poses to buildings, an analysis of the risks that buildings pose to railway infrastructure, and an analysis of the risks involved in constructing and maintaining buildings over the track. In addition, a risk analysis covering the internal safety of the railway infrastructure is needed when a wide section of it is built over.

Analysis of current rules and regulations on safety revealed some important blind spots, and these need to be filled in if we are to make appropriate risk analyses with regard to building over and near railways. Firstly, regulations need to allow more room for measures along the transmission path of a risk and at the potential victim, rather than just at the source. Secondly, it is essential to include the third dimension in risk analysis, as existing generally accepted two-dimensional models do not match current development plans involving the intensive and multiple use of space. Thirdly, the use of one contour for all types of accident needs more differentiation, as different risks have different probabilities and different effect ranges. It might also be worth considering abandoning the risk contour for individual risk for line infrastructure. Finally, it is of the utmost importance that the spatial context of projects be considered in risk analyses.

The above observations have been incorporated into a new external safety concept, the HR-3D method. This proposes ways of introducing a higher degree of differentiation into existing computer models of external safety, thereby enabling them to calculate safety more realistically. The method was used for three urban development projects, each at a different scale. In the Piazza Center project, the HR-3D method showed that it was possible to reduce individual risk by means of derailment guards and liquid drainage. The project for railway land in Dordrecht showed that the HR-3D method could be used to reduce both individual and societal risk. The Zuidas project in Amsterdam demonstrated the possibility of using the HR-3D method to differentiate societal risk. The third dimension was particularly important in this project, which involves tunnels with buildings up to 100 m high overhead. The HR-3D method brings risk reduction closer to reality, for both individual and societal risk. It forms an interesting intermediate step between generally accepted risk calculation models and complex quantitative risk analyses in projects involving multiple and intensive use of space, in which different types of accident, different effects and different measures are dealt with in a differentiated fashion.

On the basis of the research in the two previous chapters and this chapter on physical safety, the next chapter will deal with possible structures for building over railway tracks, and their costs.

164 Introduction

Chapter 8 Structural design

This chapter discusses the structural design of buildings over railway infrastructure. We shall be looking at basic structural design principles and comparing them with the conclusions of Chapters 5 to 7 regarding quality, flexibility, technical aspects and physical safety. We shall also model the basic structural design principles and perform calculations for different directions of span over tracks, different lengths of span and different building heights. Modelling a standard building over the tracks will allow us to calculate the extra costs of an over-track primary bearing structure for use in the financial analysis (Chapter 9). We shall begin with a description of the basic railway and building grids that are stacked on top of one another when railway infrastructure is built over.

8.1 Railway grids

The railway grids determine the spaces and locations available for the structures of buildings above. This section will identify the basic dimensions for railway infrastructure and discuss the locations at which buildings can be constructed over railways.

8.1.1 Structure gauge

Structure gauge < The railway grid is determined by its width and hence by the dimensions of a train. Trains need enough space not only to move in a straight line but also to

negotiate curves. The width of the structure gauge 6000 - 6800

is 4.50 m and the minimum clearance under an 4500 over-track structure is 6.00 m. The height of the structure gauge may rise to 6.80 m on a 25 kV a.c. network with trains running at 300 km/h. However, the electrification system and speed do not affect the 1435 width of the structure gauge.

165 14 Rail Estate 18 14 18

7 7 11.5 7 7 11.5 6 6 6 6 6 6 6 6

3 3 3 1.75 4.5 1.75 3 3 3 3 3 3 1.75 4.5 1.75 3 3 3 4.25 2.75 2.75 4.25 2.75 4.5 4.25 4.25 2.75 2.75 4.25 2.75 1.75 32.75 3 4.5 3 1.74.25 5 2.75 2.75 1.75 3 3 3 1.75 2.75

11.5 11.5 14 18 14 18

8.1.2 Different locations for buildings over railways < Projects involving new buildings over tracks are generally located in densely-populated urban Minimum areas and hence are sited over existing railway infrastructure, not new lines. The local layout foundation grid for an overhead of railway infrastructure plays a major role in the design of over-track buildings. There are building with four types of location at which buildings can be constructed over tracks. columns on the platforms Location Type 1: Platform area < < Within a station, the positions of platforms and tracks are usually fixed. Where there is Minimum enough space, structural elements can be sited beside the tracks, between the tracks or foundation grid for an overhead on the platforms. building with columns between Placing columns beside or between the tracks has the advantage of conserving space on the the tracks platforms for passenger use and giving passengers a better overview of the platform area. This option provides more transfer space and may discourage crime. The disadvantage is that a column between the tracks is more likely to be hit by a derailed train. Furthermore, there is not enough space between the tracks in most cases. The minimum foundation grid for overhead buildings on columns between the tracks will be about 18 m (inside dimensions), i.e. the width of the structure gauge twice (2 x 4.50 m = 9 m) plus the width of an island platform (9 m). An island platform needs a minimum width of 9 m, consisting of two times 3 m transfer space for passengers on either side and 3 m in the middle for stairs and lifts. In some cases, when the island platforms are accessible from the end, as in a terminal station, only 6 m is needed, as the space for stairs and lifts in the middle of the platform can be omitted. Such situations are rare, however.

Placing columns in the middle of the platform is the other alternative. One advantage of this approach is that a derailed train will not hit the columns, but will be guided by the platforms. Another advantage is that the span over the track can be reduced to a minimum of 14 m (inside dimensions), because platforms on the sides only need a transfer space for passengers of 3 m. It may be logical to build from the middle of the island platform to the middle of the next platform, integrating the space needed for stairs and lifts. This will lead to a minimum foundation grid of 17 m for the overhead buildings. Construction in the middle of the platforms is possible during railway operations, which is also an advantage.

The length of the platforms permits the use of a two-dimensional grid for the buildings overhead. On the longitudinal axis (i.e. along and parallel to the platforms) the designer is free to

166 Structural design

standardise on a convenient spacing between supporting structures. Along the transverse axis, however (perpendicular to the platforms), the grid is determined by the positions of platforms and tracks. And this imposed grid does not always comply with a standard building grid. If the platforms are wide enough, it is possible to place columns slightly to one side of the platform centreline to influence the grid of the primary span. The foundation grids for overhead buildings mentioned above correspond to minimum spacings for new situations. As railway lines and stations have been constructed for over 150 years, situations vary considerably, e.g. many island platforms are less than 9 m wide. Platforms wider than 9 m are, however, also found.

Location Type 2: Sidings

The sidings < At the end of the platforms, tracks converge to outside Utrecht form sidings. This area includes large numbers Centraal; crossing of switches and crossings. These are essential tracks leave little room for to the flexibility of the railway system, but they foundation grids do leave very little space for columns between the tracks. As a result, it is not usually possible to build to a grid. Even where there is room for columns between tracks, it is not always advisable to erect them here as they would limit the options for changing track layout in the future. Where possible, structures over these tracks will consist of one or two spans, but the number of spans must be kept to a minimum. If the tracks are clearly divided into one set carrying traffic in one direction and another set for the opposite direction, one option would be to place the supporting structures for overhead buildings between these two sets of tracks.

Location Type 3: Parallel tracks The third type of location is away from stations, where tracks run more or less parallel. In most situations, there will be two or four parallel tracks. One important difference by comparison with building over a platform area, which also has parallel tracks, is that there are Railway grid over fewer requirements regarding the spatial quality below the overhead building, as there are parallel tracks no passengers there. without a platform area. 1.50 m is 14 18 14 18

left open as an 7 inspection7 path. < 11.5 7 7 11.5

Railway grid over parallel tracks without a platform 6 6 6 6 6 6 6 6 area, with columns between the tracks. Two 1.50 m paths

4.25 2.75 2.75 4.25 3 3 3 1.75 4.5 1.75 3 3 3 2.75 1.75 3 3 3 3 1.75 32.75 3 1.75 4.5 1.75 3 3 3

are left open for 2.75 4.5 4.25 4.25 2.75 2.75 4.25 2.75 4.5 4.25 2.75 1.75 3 3 3 1.75 2.75 inspecting both < <

11.5 14 11.5 tracks. 18 14 18

167 Rail Estate

The minimum foundation grid for overhead buildings can be about 11.50 m (inside dimensions). Where there are two tracks, a space must be reserved to inspect them. When a foundation is also placed between the tracks, two inspection paths are needed. This may reduce the minimum foundation grid to 7.00 m (inside dimensions), leaving even less flexibility.

Location Type 4: Yards Yards are used for parking trains and also have < The railway yard at a logistic function. Such activities as minor main- Watergraafsmeer tenance are usually carried out here. These in Amsterdam. A railway yard can yards take up large sites close to the city centre be built over by and consist mainly of parallel tracks. Building removing some over railway yards can be compared to building of the tracks to over terminus stations, but the construction create a feasible foundation grid for process is simpler, as tracks can more easily be overhead buildings. taken out of service. There are no platforms for passengers, but the options for column placement between the tracks remain limited. Build- ing over a yard will involve removing some tracks to make room, as a result of which it becomes possible to build over bundles of tracks.

8.2 Building grids

The location will determine the type of railway grid adopted. This section will discuss standard office grids and will outline basic office floor layouts for a ‘standard’ building over railway infrastructure. We shall use these basic office layout to compare structural solutions.

8.2.1 Standard office grids and floor layouts Dutch offices are generally built on a 1.20 m or 1.80 m grid. This grid leads to offices 5.40 m, 6.00 m, or 7.20 m deep. A standard office grid makes it possible to use standardised building elements and to simplify the construction process. Modular partitions and office furniture are also designed in accordance with this pattern. To identify feasible structural approaches to building over railway infrastructure, this study will assume office grids of 5.40 m and 7.20 m. We have not included a 6.00 m grid, but this would also be an option.

The model building that will be used has a depth of 14.40 m, i.e. two grids of 7.20 m. This depth is common in the Netherlands for office buildings with standard rooms. A 12.60 m, with 2 x 5.40 m office depth and a hallway of 1.80 m is also common. A 14.40 m grid can also be used for innovative office concepts, such as the combi-office [Dobbelsteen, 2005]. This depth allows sufficient entrance of daylight and standardisation of office layout and furnish- ings. The length of the office is taken as 43.20 m. This is arbitrary, but does correspond to 6 x 7.20 m or 8 x 5.40 m (both 43.20 m in total). The building will have a gross floor area of 622 m2 per floor level. The floors will span 7.20 m. The figures below show two standard office layouts; 7.20 m x 5.40 m and 7.20 m x 7.20 m.

168 Structural design

A model office < 4 building measuring 4 2 5. 5. .2 7. 14.40 m x 43.20 m 7 8 2 8 4 1. (622.08 m ) on a 1. 7.20 m x 7.20 m 14.4 14. 2 2 2

grid 7. 7. 2 7. 7.

7.2 7.2 7.2 7.2 7.2 7.2 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4

43.2 (6 x 7.2 m) 43.2 (8 x 5.4 m) A model office < 4 building4 measuring 2 5. 5. .2 7. 7 14.40 m x 43.20 m 8 2 8 4 1. (622.08 m ) on a 1. 14.4 7.20 m x 5.40 m 14. 2 2 2

grid 7. 7. 2 7. 7.

7.2 7.2 7.2 7.2 7.2 7.2 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4

43.2 (6 x 7.2 m) 43.2 (8 x 5.4 m)

8.2.2 Combinations of different railway spans with standard office grids The intervals between supporting structures for the model 43.20 m x 14.40 m building will vary according to the situation. In this study, we shall look at a number of standard spans based on the 7.20 m and 5.40 m grids.

Using these two standard grids, the length of the primary span can be two, three or four times 7.20 m (14.40 m, 21.60 m, or 28.80 m) and two, three, four or five times 5.40 m (10.80 m, 16.20 m, 21.60 m, or 27.00 m). Spans based on combinations of 5.40 m and

7.20 m are also possible. Possible standard < railway spans based on a 5.40 m or 7.20 m grid

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7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 8.2.3 Perpendicular and longitudinal positioning The model building can be positioned along the tracks or perpendicular to them. 3.6

Option 1: Building7.2 perpendicular to tracks

a) 7.20 m grid 3.6

7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 Overall spans of 14.40 m, 21.60 m and 28.80 m are possible. If an overall3.6 span of 7.2 7.2 14.40 m is 7.2 chosen, the building will have three spans (43.2 / 14.4 = 3) and at 21.60 m the building will have two spans. If the overall span is 28.80 m, the building will also3.6 have

two spans, but it will be longer: 57.60 m (2 x 28.80 m). 3.6 7.2 7.2 7.2 7.2 3.6 b) 5.40 m grid

3.6 14.4 A 10.80 m overall span gives four spans. An overall span of 16.20 m gives three spans 21.6 7.2 7.2 7.2

and the building will be 48.60 m long. With an overall span of 21.60 m, the building3.6 will 21.6 21.6 have two spans of similar length to those in the variant with a 7.20 m grid. For an overall 7.2 7.2 7.2 7.2 span of 27 m,7.2 the building will have two spans and will be 54 m long.

14.4 21.6 7.2 7.2

21.6 21.6 7.2 7.2 7.2 7.2 43.2 (6 x 7.2 m) 43.2 (6 x 7.2 m) 7.2 7.2 7.2 7.2 5,4 7.2 7.2 7.2 7.2 7.2 1,8 14.4 43.2 (6 x 7.2 m) 43.2 (6 x 7.2 m) 7.2 7.2 7,2 7.2 7.2 7.2

< Floor plan of a standard office 5,4 7.2 7.2 7.2 perpendicular to 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2

1,8 the tracks, with a

14.4 7.20 m x 7.20 m 7.2 grid 7.2 7,2 7.2 43.2 (6 x 7.2 m) 14.4 14.4

7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2

Tracks Tracks

Platform Tracks Tracks Platform Platform Platform Platform Platform Platform

Tracks Tracks Tracks Tracks Tracks Tracks

43.2 (6 x 7.2 m) 14.4 14.4

Tracks Tracks

Platform Tracks Tracks Platform Platform Platform Platform Platform Platform

Tracks Tracks Tracks Tracks Tracks Tracks

170 Structural design

Option 2: Building oriented longitudinally to the tracks Here, only the 7.20 m grid is convenient, as the building has a depth of 14.40 m, which is twice 7.20 m. We shall consider three railway grids: 14.40 m, 21.60 m and 28.80 m. If the building is oriented longitudinally to the tracks it will only have one span. If the supporting structure is 21.60 m or 28.80 m wide, it will be wider than the office itself, which is only

14.40 m deep. 7.2 7.2 7.2 < 7.2 7.2 7.2 7.2 7.2 Cross sections of possible standard offices oriented

3.6 longitudinally 7.2 to the tracks. 3.6 14.40 m span on

3.6 the left, 21.60 m 7.2 7.2 span on the right. 7.2 3.6 Both offices have a 7.20 m x 7.20 m 7.2 7.2 grid. 7.2

14.4 21.6

21.6 21.6 Floor plans of < possible standard 7.2 offices oriented 7.2 longitudinally to the tracks. 7.2 14.40 m span on 7.2 the left, 21.60 m span on the right. 7.2 Both offices have a 7.2 7.20 m x 7.20 m grid. 43.2 (6 x 7.2 m) 43.2 (6 x 7.2 m) 7.2 7.2 5,4 7.2 7.2 7.2 1,8 14.4 7.2 7.2 7.2 7,2

7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2

43.2 (6 x 7.2 m) 14.4 14.4

Tracks Tracks Platform Platform Platform Platform Platform

Platform Tracks Tracks Platform

Tracks Tracks Tracks Tracks Tracks Tracks

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8.3 Structural design principles

We can derive different principles for the structural design of buildings over railways from the degree to which they match the grid of the railway infrastructure. • The track-derived structure matches the railway infrastructure exactly, and the imposed grid is used for all floors. • The transfer structure partially adapts to the railway infrastructure. The structural grid of the foundation points is derived from the tracks, but an intermediate structure transfers this railway grid to a grid convenient for an overhead building. The grid of the building therefore differs from that of the tracks. • The mega transfer structure is completely independent of the railway infrastructure. This approach makes it possible to build over the railway infrastructure in one span, with a convenient grid for the buildings.

We shall now discuss these types in detail, along with real-life examples.

8.3.1 Track-derived structures A track-derived structure is a structure that corresponds to the grid imposed by the tracks. The distance between the spaces where columns can be placed between the tracks forms the basis for this type of structure. The height between the floors is greater than for a standard building, as the longer span demands a deeper beam. For a span of 21.60 m, the floor height will be approximately 4 m (3.30 m free storey height + structure).

< Scheme for a track-derived 4 structure with a span of 21.60 m 4 4 4 (3.6 + 10%) 7.2

21.6 21.6

A track-derived structure can be used at the various locations over the tracks discussed earlier in this chapter. The structure is not necessarily bound to spans of n x 5.40 m or n x 7.20 m. For this structure, it is important to minimise the length of the span. Yards and parallel tracks are the most suitable locations. In such locations, strip footings for columns can be placed at multiples of 4.50 m apart (4.50 m being the width of the structure gauge

172 Structural design

for one single track) + some space for a passageway. Two tracks and a passageway will require about 11.50 m. The structure can also be placed over the platform area, with railway spans similar to those in 8.1. Track-derived structures are not very suitable over sidings; because placing lines of columns beside the tracks is difficult due to switches and signals; the spans will become too large for this type of structure.

SECTION THROUGH RAFT LOOKING SOUTH

13,500 l

New girder to receive

Existing cementious fire 0 < structure to protection The foundation be removed 1600 typica 80 grid of the columns 2850 Clear Platform under 135 – 199 Platform 18 Platform 17 Platform 16 Platform 15 Platform 14 Platform 13 Platform 12 Platform 11 Bishopsgate in London is based Existing wall footing on the distance New strip footings placed in three sections Existing wall footing between the island platforms. The 13.50 m grid is The buildings of 135 – 199 Bishopsgate in London are an example of a track-derived struc- used for all the ture. These have been built above Platforms 11 to 18 of Liverpool Street Station and are floors of the eight to ten floors high. The columns are placed in the middle of the platforms and the pri- building overhead. mary structure spans 13.50 m. This is possible because the island platforms have a width of only 5.70 m; they are narrower because they do not include a zone for stairs and lifts, as they can be reached from the concourse, Liverpool Street being a terminus station. The first floor over the tracks was over-dimensioned so that the rest of the building could be constructed on it, thereby minimising disruption to railway traffic.

8.3.2 Transfer structures Transfer structures can be used to convert an unfavourable grid dictated by platforms and tracks into a feasible or even a standard grid for an overhead building. Transfer structures take loads where they can conveniently be collected and transfer them to where they can

7.2 7.2 7.2 Scheme of a <

transfer structure 3.6

with a 21.60 m 7.2

span. The 21.60 m 3.6 foundation grid is

converted into a 3.6

convenient grid 7.2

of 7.20 m for 3.6 all layers of the building. 7.2

21.6 21.6

173 Rail Estate <

conveniently be resisted [Bird, 1993]. The transfer structure serves as an intermediary A concrete between the imposed grid of the tracks below and the desired grid of the buildings above. transfer structure as an artificial The use of a truss is logical, as bearing points can be created for the buildings directly ground level in above the trains. Large concrete beams (as much as one storey high) can also be used. Seine Rive Gauche. When the transfer structure is made one or two floors high, the space can be used for The transfer parking facilities and building services. These floors can also serve as a buffer between structure layer acts as a car park the tracks and the buildings in case of an accident. Transfer structures are useful where and also forms the the span is greater than a standard floor length. This kind of structure can be used at all foundation of the the locations described earlier in this chapter. In the example on the previous page the buildings overhead. transfer structure is two storeys high in order to optimise the layout of the floors. Steel is used, to create maximum transparancy. The transfer structure is most suitable for spans of about 15 m to 40 m.

The Rive Gauche project in Paris (under construction) is a good example of a transfer structure. The transfer structure uses in-situ concrete and serves as a car park. It also forms an artificial ground level over the tracks and the station.

8.3.3 Mega transfer structures If it is not possible to build on the platforms or between the tracks, a mega transfer structure can be used. A mega transfer structure is a structure with a large span over the railway infrastructure. The difference between a mega transfer structure and a transfer structure is arbitrary. For our purposes, we shall say that a transfer structure is a mega transfer structure when its height takes up more than half the building height. Normal transfer structures may

174 Structural design

use a number of spans over the tracks with a structure one or two storeys high. Mega transfer structures usually have one span over the tracks with a structure over multiple floors.

The use of a mega transfer structure is logical over sidings. Here, switches and non-parallel tracks prevent the use of any standard grid and sometimes even make it impossible to place columns between the tracks. The use of a mega transfer structure at these locations is logical because it preserves sufficient flexibility for the infrastructure. It is possible to use mega transfer structures at other locations, for instance if platforms must be kept free of columns, or when maximum track layout flexibility is required.

The Exchange House over the tracks outside Liverpool Street Station is an example of a mega transfer structure, spanning almost 80 m. Such a structure was used because no structural grid could be found between the tracks [Ridout, 1989]. An arch design is logical,

as it carries the permanent uniform load of the building. Scheme of a < mega transfer structure with an 80 m span [SOM]

8.4 General consequences of the structural design principles

The structural design principles affect quality, flexibility, technical aspects and physical safety. These aspects were discussed in the previous chapters and will be dealt with below for the track-derived structure, the transfer structure and the mega transfer structure.

8.4.1 Effects on quality A track-derived structure needs short spans, leading to a large number of columns on platforms or between tracks. This has a negative impact on quality at platform level, as the passenger’s view of the passenger is obstructed. This is not a problem when new buildings are constructed over sidings, yards or parallel tracks. The use of a track-derived structure can have a positive effect on urban quality. The height of any new artificial ground level over the tracks is limited with this structure, as the height of the structure is minimised.

175 Rail Estate <

A transfer structure allows larger spans than does a track-derived structure. It is therefore A mega transfer possible to use fewer columns under the building, reducing the obstructions to the view of structure gives passengers on the platforms. As for the track-derived structure, this is not an issue for sid- character to the Exchange House in ings, yards or parallel tracks. The quality of the overhead building is higher with a transfer London [SOM] structure than with a track-derived structure, as a transfer structure provides a standard grid and the building can have a more logical functional arrangement and less height differ- < < A mega transfer ence between floors. structure gives character to A mega transfer structure makes it possible to enhance the quality of the railway infra- Traffic Square in structure. When such a structure is used over the tracks, there are no columns at plat- Rijswijk form level, which contributes to the overview. A mega transfer structure can also add to the quality of the building overhead, giving the building character. However, these struc- The Katreinetoren tures do limit the layout of the building and will take up lettable floor space. On the other in Utrecht with hand, they share with transfer structures the advantage of allowing for a standard grid its old façade. within the building. Its track-derived structure allows no structural 8.4.2 Effect on flexibility flexibility. Track-derived structures limit the flexibility of the railway infrastructure. Every possibility for < < siting columns will be used, to limit the length of the span. This will limit scope for changing The Katreinetoren the infrastructure at a later stage. When a track-derived structure is used in a platform area, today. Replacing the layout of platforms and tracks will be fixed. the façade extended its life. <

176 Structural design

Track-derived structures have two contrasting effects on building flexibility. The first is that the tracks will dictate the building grid. There is flexibility lengthwise to the tracks, but the structure of the building is fixed. The Katreinetoren in Utrecht is an example of a fixed, track- derived structure. Only the façade of the building can be changed. One positive feature, however, is that a track-derived structure with longer spans enhances the flexibility of the floor layout, as there will be fewer columns.

7.2 7.2 7.2 7.2

7.2 7.2 7.2 7.2 <

A transfer 7.2 structure can create scope for 7.2 changes in the layout of railway 7.2 infrastructure at a later stage. Such 7.2

changes are rare, 7.2 but this approach

can certainly be 7.2 of use when such changes are expected. 28.8 28.8

28.8 28.8 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6

28.8 28.8

A transfer structure may increase the flexibility of both the railway infrastructure and the buildings over it. They can be so designed as to leave scope for moving the columns between the tracks. There are different bearing points in the transfer structure itself, e.g. at intervals of 7.20 m, 6.00 m or 5.40 m, depending on the transfer structure grid. Although rare and difficult to achieve, this is a form of flexibility that can be designed into an over-track transfer structure.

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< The use of a transfer structure gives flexibility to overhead structures. The overhead buildings can be modified or even demolished 28.8 28.8 28.8 28.8 and replaced by new buildings on the same foundation points. A transfer structure can also add flexibility to the overhead building. Transfer structures act as a collection of bearing points. If provision is made when designing the transfer structure, it will be possible to modify the overhead building at a later stage. When the transfer structure itself functions as an artificial ground level, it may be possible to demolish an overhead building and rebuild on the same bearing points without disrupting railway operations. In this way the transfer structure can have two functions: a structure that bears the weight of an overhead building and an artificial ground level on which buildings can be constructed wherever required. In addition, the transfer structure itself can be used for one or two floors, utilising the space between the transfer structures.

A standard grid can be used for a building within the mega transfer structure. One disadvantage of these structures is that changes to the building are difficult. It will also be difficult to demolish the building once it reaches the end of its economic life. A mega transfer structure makes it possible to freely reposition the tracks after the building is finished, but increasing the number of tracks will be difficult, as the large foundations of the mega structure enclose the tracks. In other words, a mega transfer structure allows scope for changing railway infrastructure, but restricts the scope for extending it.

8.4.3 Technical implications Chapter 6 discussed three important technical aspects of building over tracks: noise, vibration and electromagnetic compatibility (EMC). The choice of structural design has little or no effect on noise and EMC, so we shall restrict our discussion to the effects of the three structural design solutions on vibration.

Track-derived structure: Because the track-derived structure is a framework with large spans, it will be heavy. Because of the higher mass, vibration has less impact on the structure. Further- more, the eigenfrequency is a function of the deflection in mm. A large deflection, as is the case for a beam with a large span, gives a low eigenfrequency, which helps limit vibration nuisance.

Transfer structure: The transfer structure has a larger number of elements, and these elements are lighter, because of the standard 7.20 m grid. This results in a lighter structure, the elements of which have a higher eigenfrequency. This eigenfrequency will be closer to the frequencies of train-induced vibration. That can partly be overcome by making the structure stiffer. It is also possible to incorporate friction connections, which damp structural vibration by dissipating energy. The precise effects need to be determined for each project.

178 Structural design

Mega transfer structure: The mega transfer structure will transfer the load of the building to the ground on both sides of the tracks. There will be more weight at these points, which is better from a vibration point of view, because vibration has less impact on a higher mass. However, the rest of the building will be relatively light. Here again, the precise effects on vibration can be determined in practice.

8.4.4 Effects on physical safety The three structural design principles have different effects on physical safety. In this para- graph, we shall discuss three aspects of physical safety: mechanical failure leading to progressive collapse, fire safety and safety during construction.

Progressive collapse is a specific point of attention, as progressive collapse in case of a local structural failure can cause major damage. Starossek and Wolff define three strategies for designing collapse-resistant structures: specific local resistance, alternate load paths and isolation of collapsing sections [Starossek & Wolff, 2005]. We shall be examining the effects of the different structural design solutions on these strategies.

Track-derived structure: The beams and columns of a track-derived structure are very robust as they have large sections, due to the long spans. This leads to high specific local strength. For the structure as a whole, however, there are drawbacks to using a limited number of large structural elements. The structure depends more on the strength of each element; it is less resistant to progressive collapse because of the limited number of elements. The loss of a single element, e.g. in a fire, will affect the whole building. This can lead to progressive collapse, which also poses a major risk to the railway infrastructure underneath. As a result, each individual element of a track-derived structure must be designed with specific local resistance.

If a track-derived structure consists of large concrete elements, local fire resistance will be good. Such structures will be relatively insensitive to fire.

During the construction phase of the building, there is also the risk related to assembling larger elements over the railway infrastructure. If one of those large elements falls, it will cause much more damage to the railway infrastructure than a smaller beam or column. It might be necessary to close the tracks below throughout construction of the primary bearing structure. The beams and columns of a track-derived structure will weigh between 1 000 kg and 10 000 kg. According to Suddle, the probability of structural collapse due to elements of this kind of weight falling during construction is ten times higher than for elements weighing between 100 kg and 1 000 kg [Suddle, 2004].

Transfer structure: A transfer structure can provide a higher level of physical safety than a track-derived structure. Designs to prevent progressive collapse can be based on specific local resistance and on alternate load paths. Compared to a track-derived structure, the individual elements of a building supported by a transfer structure are less robust and have lower specific local resistance. However, the combination of these smaller elements (beams 7.20 m long, lighter columns and a larger number of columns) provides more alternative load paths if an individual element fails. A transfer structure makes it possible to give the

179 Rail Estate

< A transfer structure has an overhead building with smaller spans. By creating alternative load paths, the building as a whole has more resistance 2 7. to progressive 2 7. 7.2 7.2 7.2 7.2 collapse.

overhead structure a finer grid than a building of stacked track-derived structures and it can be so designed as to prevent progressive collapse. This can be achieved by fixing all joints rigidly, creating an alternative load path and thereby reducing the risk of progressive collapse. However, the members of the transfer structure itself will require specific local resistance, as progressive collapse could occur more easily if one were to fail.

A transfer structure can be made of steel or concrete. In case of fire, a steel frame has disadvantages, as the structure can collapse when an intense fire directly heats the steel. It is advisable to apply a higher degree of fire protection to the transfer structure, certainly with respect to fires in trains that can subject the transfer structure to direct radiation. One option is to place the transfer structure one floor higher to protect it, and to accept the loss of the lowest floor in case of a train fire. The lower floor can be suspended from the transfer structure. Research by Van Diermen indicated that placing the transfer structure one floor higher also has a positive effect in case of an explosion [Diermen, 2004]. The lower floor is lost, but the rest of the building can be saved. However, placing the transfer structure one floor higher creates horizontal stability problems that must be resolved.

A transfer structure also has advantages over a track-derived structure for the construction stage. The transfer structure itself needs a specific operation when put into place, but thereafter it may be possible to assemble the building using smaller structural elements, while the railway infrastructure remains in service. The transfer structure can function as a

< It is possible to prevent structural failure of a transfer structure in case of fire or explosion by suspending the lower floor from the transfer structure

180 Structural design

crash deck during this construction phase after a floor with sufficient strength is put in place. Research by Suddle indicates that structural elements of 100 kg to 1 000 kg (the weight range of the columns and beams constituting a transfer structure) are ten times less likely to cause collapse of the overall structure if they fall during construction than the 1 000 kg to 10 000 kg elements used in a track-derived structure [Suddle, 2004]. Columns on the edges of the building need special attention during assembly, but the rest of the elements can be placed while trains are running after erection of the first floor.

Mega transfer structure: Mega transfer structures over tracks need large lower columns beside the tracks. This has an advantage for safety. Large elements are less sensitive to fire and mechanical loads, such as colliding trains. They may even resist small explosions. Like transfer structures, mega transfer structures can be so designed that a fire or an explosion leads to the loss of the lowest floor, while saving the rest of the building by preventing progressive collapse. Putting a mega transfer structure into place is a bigger challenge, and the tracks will have to be closed while this is done.

8.5 Basic structural design

Structural design is based mainly on local constraints. The layout of the tracks to be built over determines the degree of freedom to choose a structural principle. The structural design parameters are: the options for placing columns between the tracks, the direction and length of the primary span, the elements required to ensure the stability of the structure, the different types of foundation, the materials and the connection between the structure and street level. This section will also address construction aspects. All these elements form the basic input for the structural design.

8.5.1 Length of the primary span The length of the primary span will differ according to the location, as the options for placing columns between the tracks will vary, as will flexibility requirements. If columns can be placed between every track, it is theoretically possible to limit the span to about 7 m (the width of the structure gauge for one track, plus an inspection path). Where columns coincide with island platforms, this span will be about 14 m to 20 m. If all the tracks must be spanned in one go, the length may rise to over 80 m. The length of the primary span is related to the location.

Parallel tracks and yards Platform area Sidings

A rough indication < Primary span [m] 10 20 30 40 50 60 70 … of the relationship Track-derived structure between structure type and span Transfer structure or mega transfer structure length

181 Rail Estate

8.5.2 Direction of primary span If the building span is limited to about 15 m and the tracks run parallel, the primary span can run longitudinal to the tracks. This has the advantage that the structure can be placed between the trains instead of above them. The result will be that the total height between the tracks and the new artificial ground level overhead is less than if a transverse structure with a girder above the tracks were used. In effect, one will have ‘saved’ approximately the difference between the height of the primary span and the height of the secondary span. If a floor span transverse to the tracks is possible, it is possible to save about a metre of height from ground level to artificial ground level. If the primary span is perpendicular to the tracks, the secondary span will be standardised for the use of a normal floor system in the longitudinal direction.

Concrete floor slab < A primary span Primary span lengthwise to the tracks needs less 7.20 7.60 height because it is placed ‘between’ the trains. A 14.4 primary span perpendicular to the tracks is placed directly above, and the overall height

Concrete floor slab is greater.

Primary span 8.60 7.20

14.4

8.5.3 Stability The stability of the structure must be ensured in two directions: longitudinal to the tracks and perpendicular to them. In the longitudinal direction, it is possible to ensure stability by erecting bracing between the tracks. It is much more difficult to ensure stability perpendicular to the tracks, as the wind moment that must be taken up needs a certain width. In most cases, the space between the tracks is just enough for one column. Wind moment can be resisted in two places: the foundation or the structure. If wind moment is taken up in the foundation, space for a stability element has to be found between or beside the tracks. The wind moment can also be taken up in the structure itself by using various designs of moment-resisting frame.

182

Structural design It is possible to < ensure horizontal stability by taking up the wind moment in the foundations. The necessary structure can be placed beside or between the tracks, or possibly

on the platforms. It is also possible < to take up the wind moment using a moment-resisting frame

The means used to achieve horizontal stability will affect the vertical loads in the foundation. A stabilising structure beside the track that takes up the wind moment in the foundation can cause upward forces on the foundation. This upward force is difficult to handle and a foundation that can withstand upward vertical forces is more expensive. To compensate upward vertical forces, a vertical load can be introduced, for instance by placing part of the building beside that track as an extra vertical load.

A stabilising < structure beside the track can generate an upward load. An upward load in the foundation can be avoided by exerting more downward force and better dividing the total downward force. 8.5.4 Foundations As discussed in Chapter 3, it is possible to position tracks at different levels: under ground, at ground level, or at Level +1. The vertical position of the tracks determines the type of foundation used for the overhead building. There are three types of foundation: tracks in tunnels (subsurface being similar to tunnels), at ground level and above ground level. These will be discussed briefly below.

A tunnel can function as a foundation for a building overhead. In the Netherlands, tunnels are often designed to withstand the upward force due to underground water pressure. This upward force can be compensated by the weight of the building overhead. One example is the Equinox building above the Utrechtsebaan motorway in The Hague.

183 Rail Estate

7.2 7.2 7.2

7.2 7.2 7.2 7.2 An overhead building compensates upward 7.2 7.2 7.2 water pressure. Upward water pressure Tunnels can can also be used to withstand the weight < function as of the overhead building and thus carry foundations for more floors. However, the tunnel must be overhead buildings designed with foundation points that can take the loads imposed by the overhead buildings. There is also a degree of lengthwise complexity to the tunnel; some parts of it will not be subjected to the vertical load of the overhead building, which complicates connections between different parts of

the tunnel, as deformation will not be uni- 21.6 21.6 form along its length. Tunnels also have an advantage for horizontal loadings, in that 7.2 7.2 7.2 they can contribute to the horizontal stabil- 7.2 7.2 7.2 7.2 ity of the overhead7.2 building.7.2 Again,7.2 connec- 21.6 tions between tunnel parts will need care- < Foundations for ful consideration because of differential a building over deformation. tracks at ground level When the tracks lie at ground level, the foundation will have to be placed beside or between the tracks. The downward forces are concentrated over a smaller area than in a normal building, and linear footings may be required. Instead of normal pile foundations, it may be necessary to use more expensive bored piles, which are capable 21.6 21.6 of reacting a larger load each. Bored piles will be required in any case as pile-driving is not allowed close to railway tracks. Con- 21.6 centrated loads directly beside the tracks 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 may also influence their position, which is a < Foundations for risk for railway operations. The means used buildings over to achieve stability are similar to those dis- tracks above cussed in the previous section. ground level need extra consideration because of Tracks above ground level constitute an horizontal stability even greater challenge for the foundations of an overhead building. First of all, the horizontal forces must be brought to ground level, which is much more expensive due to the extra height. Secondly, the foundation must pass through a dike or even an

21.6 21.6 184

21.6 Structural design

existing viaduct structure. Columns are some metres longer, and if the structure has to be built through an existing track structure the costs will be even higher.

8.5.5 Materials Both concrete and steel can be used when building over railways. Local tradition plays an important role in the choice between steel, concrete or even high-strength or composite materials (see Chapter 4). For instance, steel is used for over-track structures in England while concrete is used in France. Indeed, tradition can play a more important role in the choice of material than the objective advantages of a given material for a given location. New high-strength concrete or steel components may be of interest in the future, as they are lighter and hence easier to build with. Demands on stiffness still require sufficient structural height. The differences between steel and concrete will be discussed briefly below.

The main advantages to using steel are that building is quicker and that there is only a limited weight to be hoisted. In addition, steel structures are relatively easy to change or extend and they are more transparent, which adds to flexibility and to the quality of the platform area. Preservation of the steel structure requires attention due to the presence of metallic particles. Furthermore, the lighter steel elements are sensitive to vibration and protection against fire is a problem.

Concrete can be used to limit noise and vibration from trains because it is heavier. However, this additional weight is a drawback during construction, as if any of these elements fall they will do more damage than the lighter steel columns. Pre-cast concrete elements are preferred over in-situ, as they reduce building time. Metallic particles have less effect on concrete than on steel. Concrete also needs less maintenance and is more resistant to fire.

8.5.6 Connection with surroundings One special part of the structure, and one which is important to the use of the buildings, is the connection between the building and its surroundings. It might not look logical to discuss this subject here, but it can influence the structure. The connection to ground level is also The offices of relevance to escape routes. A building over the tracks must be accessible, which may over Charing require the construction of bridge structures over the tracks. This is only a problem when the Cross Station in London are partly tracks lie at or above ground level, as buildings over underground tracks are directly acces- constructed beside sible at ground level. When tracks lie at or above ground level, the buildings will be situated the track, providing above street level and the route from ground level to the entrance of the building will often a direct connection to street level

[Farrell & Ove Arup] <

It is possible to connect an over-track building to ground level by constructing

part of it beside the tracks < <

185 Rail Estate < A bridge structure connects this future hotel over the tracks of Amsterdam Centraal to the existing IBIS Hotel [Ruland & Partner Architekten]. < < It is possible to connect an over-track building have to overcome a substantial difference in height. There are various ways of connecting to street level via an overhead building with street level. We shall discuss connections between ground level a bridge linking it to and the entrance to the building for tracks at ground level. When tracks are located above a building beside the track. ground level the solutions are comparable, but the height to be overcome is greater.

One way of connecting offices over tracks to ground level is to build part of the office beside the tracks, at ground level. There may even be an existing building that can fulfil this role. The part of the office beside the tracks can also be used to provide horizontal stability. An example of such an approach is found at Charing Cross Station in London.

Another option is to use a bridge structure to connect the over-track building with one located beside the track. However, this bridge structure will not contribute to the horizontal stability of the over-track building – it is merely a functional connection. One example is at Amsterdam Centraal where a future extension to the existing IBIS Hotel will be built over the tracks and connected to the existing building by a bridge structure.

A third way of connecting an overhead building with ground level is a slope or dike with a staircase or escalator, or else a lift. This connection can also be used to add to the horizontal stability of the building over the tracks, as enough space is available for the necessary structures. There is an example of a direct connection between an over-track building and street level in the Seine Rive Gauche project. Here, a staircase connects buildings over the tracks with ground level, albeit without playing a stabilising role.

Finally, it is possible to connect an over-track building to street level using an artificial ground level. In Rive Gauche, a complete artificial ground level has been built over the tracks, and the buildings on top are accessible only via the new ground level.

Buildings above In addition to enabling users to move between the buildings and street level, it will be neces- the tracks of Seine sary to provide connections for electricity, gas, telecommunications, water and sewerage. Rive Gauche are connected to street level < via stairs

Connection between an over- track building and street level via a staircase beside < < the track

186 Structural design

Buildings above < the tracks of Seine Rive Gauche are connected via an artificial ground

level Connection via < < an artificial ground level

8.5.7 Construction aspects The actual process of building over the tracks is an important design factor. Consideration should be given to the site, the time required and the noise that will be generated.

Building over railway infrastructure generally occurs in inner-city areas. Usually, the dense station surroundings only allow for a very small construction site. A small construction site demands a construction process with just-on-time delivery and small building elements. The available construction site partly determines the maximum size these elements. The maximum size of the elements is also limited by the transport routes to the site. It may be possible to move them by rail, but not always, as the railway must be remain in service. Moving building elements into inner city areas by water, if possible at all, will also be difficult because of bridges. Efficient construction will therefore be based on small building elements and just- in-time delivery. It is also important to position cranes carefully. There must be no risk of their falling onto the track or dropping materials onto it or the surroundings.

A small construction site will make the construction process more difficult. The problem can partly be solved by enlarging it, using the lower floor of a building over the tracks as an extra construction floor. If this floor is over-dimensioned, it is even possible to place building equipment on it and to build the structure up from it. Over-dimensioning the lower floor also reduces such hazards as falling materials and may make it possible to keep railway lines in service during construction.

A small < construction site for the construction of the IBIS Hotel over the tracks of Amsterdam Centraal

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Stations and tracks must remain operational during the construction of the buildings. The logistics of construction must be coordinated with train timetables. As a consequence, building time is often reduced and construction will have to take place mostly at night (01:00 – 05:00) and at weekends, when there is less train traffic. Construction at night will be more expensive and increases the risk of accidents, as visibility is poorer. Construction at night will also require artificial light, which is a nuisance to the surroundings, as is the building noise. However, it does have the advantage that fewer passengers and residents are about, which reduces construction-related safety risks.

Given the inner city environment, the regulations on building noise will limit the choices between different methods for foundations and on-site construction. For instance, pile-driving at night will not be acceptable, and it is likely that the structure will be largely prefabricated. There will also be limitations on traffic to and from the site at night, because of the noise nuisance to residents.

8.6 Cost comparison

We can compare the cost per square metre of gross floor area, both between different types of over-track structure and between over-track structures and standard structures beside the tracks. The calculations and cost estimates are at Appendix A. That comparison does not discuss the mega transfer structure separately. The main aim of comparing the various over-track structures to standard buildings was to find alternatives for spans of between 10 m and 30 m. This study does not include separate calculations for large bridge structures. We have compared the different structural solutions by calculating for different spans, different numbers of floors and different orientation relative to the tracks.

• Spans: Six different spans over tracks have been calculated for track-derived and transfer structures. The dimensions were based on possible standard grids for the overhead building on the transfer structure. Four spans were based on a 5.40 m overhead building grid: 10.80 m, 16.20 m, 21.60 m and 27 m. Three spans were based on a 7.20 m overhead building grid: 14.40 m, 21.60 m and 28.80 m.

• Number of floors: Two building heights were chosen, arbitrarily: four floors and ten. The four-floor building is considered to be a typical small building and a ten-floor building is considered to be a typical medium-sized building.

• Orientation relative to the track: As indicated earlier, a building can be constructed longitudinal or perpendicular to the tracks. For the longitudinally-oriented track-derived structure, only the 14.40 m variant was calculated, as that is the depth of the office. For the longitudinally-oriented transfer structure, only the spans with the 7.20 m grid were calculated due to the 14.40 m depth of the office (2 x 7.20 m).

188 Structural design

The primary bearing structure of a standard building was calculated at € 120/m2 based on a 7.20 m primary span and a 7.20 m transverse floor span, similar to the structure of a building on a transfer structure. This 120/m2 only includes the costs for the primary bearing structure, the floors and the fire-resistant coating for the steel structure. All other costs will be discussed in Chapter 9.

The primary bearing structures for a four-floor overhead building are of course more expensive than a standard primary bearing structure. The track-derived structure turns out to be 48% to 159% more expensive: € 178/m2 to € 310/m2 compared to € 120/m2. The transfer structure has more variants because of the extra options for longitudinal positioning over the tracks. Transfer structures for four-floor buildings over tracks are 38% to 97% more expensive than standard primary bearing structures. The effect of the extra investments on

the total development will be discussed in Chapter 9. < Costs of bearing structures for four floors Costs of a 350 four-floor primary 5.40 m grid, transverse 7.20 m grid, transverse bearing structure 300 7.20 m grid, longitudinal over tracks. Track-derived 250 ] 2 200

€ /m Track-derived [ Transfer 150 Cost

Standard 100

0 1.80 3.60 5.40 7.20 9.00 10.80 12.60 14.40 16.20 18.00 19.80 21.60 23.40 25.20 27.00 28.80 Primary span over tracks [m]

The extra costs of a primary bearing structure for a building of ten floors over railway infrastructure differ from the extra costs for a four-floor building. For the track-derived structure, the difference compared to the four-floor variants is minimal, 41% to 136% or € 169/m2 to € 283/m2. The reason for the differences not being larger is that the costs of a track-derived structure are almost the same per floor, because every floor has the same beam (based on the span) and only the costs for the lower columns are divided over more floors. The beams make up 80% of the costs. The transfer structures become relatively less expensive for more floors, as the costs for the trusses are divided over more square metres. The extra costs of a transfer structure are 19% to 67% or € 142/m2 to € 200/m2.

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Costs of bearing structures for ten floors 350 < Costs of a 5.40 m grid, transverse ten-floor primary 7.20 m grid, transverse 300 bearing structure 7.20 m grid, longitudinal over tracks. Track-derived 250 ] 2 200 € /m [ Track-derived 150 Cost Transfer

Standard 100

0 1.80 3.60 5.40 7.20 9.00 10.80 12.60 14.40 16.20 18.00 19.80 21.60 23.40 25.20 27.00 28.80 Primary span over tracks [m]

In all situations, the primary bearing structure of the track-derived structure is more expensive than that of a primary bearing structure with a transfer structure. This cost difference increases substantially at greater spans. The difference between the two types in terms of the rate at which costs increase with span lies in the way they function. The track-derived structure is designed on stiffness, or conversely on the deflection of the beam. The costs per square metre increase because the deflection is proportional to the span to the power of four. However, the costs of the longer beams themselves do not increase to the power of four. The transfer structure is designed on the strength of the bars and the height of two floors, not on stiffness. Its strength is proportional to the span length squared, so costs per square metre increase more slowly with span compared to the track-derived structure.

We may conclude that the cost of a track-derived structure is only comparable with that of a transfer structure at shorter spans. At a span of 15 m, one can reasonably use either. At longer spans the track-derived structure is much more expensive.

There are, of course, other cost components to a building over tracks. The costs of the primary bearing structures are just one of the elements that will be discussed in the comparison between buildings beside and over tracks in the next chapter.

8.7 Conclusion

The design of structures to support buildings over the track involves superimposing different grids. Railway infrastructure yields four possible generic locations, but railway grids will differ according to the specific location and it is not possible to give a generally-valid span length. In contrast with the railway infrastructure, buildings have standard grids that can be used at all locations. These standard grids are 5.40 m, 6.00 m and 7.20 m, and combinations of these

190 Structural design

three are possible. To place buildings over railway infrastructure, the standard grids of the buildings have to be so combined as to match the span over the railway infrastructure. This makes it possible to place an optimal structure over the tracks.

Three types of structure can be used to build over railway infrastructure: the track-derived structure, the transfer structure and the mega transfer structure. The track-derived structure simply follows the railway grid. The transfer structure is an intermediate layer that converts the unfavourable railway grid to a grid compatible with the buildings. The mega transfer structure is a specific type of transfer structure of which the height makes up more than half the building height. It also provides a convenient grid for the buildings it supports. The track-derived structure has the advantages that it adds comparatively little height when it is used to create an artificial ground level over the tracks and that it gives more freedom in the functional arrangement of the floors, because there are no columns inside the over-track building. Transfer structures offer building flexibility and, to some extent, track flexibility. They also enhance physical safety. Mega transfer structures allow considerable track flexibility and may enhance the quality of the building, as they usually function as landmarks.

To compare track-derived and transfer structures, we produced a basic structural design for each type of structure, and for each type we examined two orientations – perpendicular to the track and longitudinal to it. We performed calculations for six different span lengths and two different building heights. The design revealed the existence of specific challenges regarding the stability of the structure, the foundations, the connection to street level and the construction process.

The costs of the structures were also compared. In all situations, the track-derived structure is more expensive than the transfer structure. For short spans (up to 15 m) the costs are comparable, but for longer spans the track-derived structure is far more expensive than the transfer structure. The costs were also compared to those of the bearing structure of a standard office without large spans, which are estimated at € 120/m2. The track-derived structure is roughly 50% to 160% more expensive for a four-floor office and 40% to 140% more expensive for a ten-floor office. The transfer structure is roughly 40% to 100% more expensive for a four-floor office and 20% to 70% more expensive for a ten-floor office. A transfer structure becomes more cost-effective when there are more floors, whereas more floors do not significantly increase the cost-effectiveness of track-derived structures, however, because the beams make up 80% of the costs and they are similar for both building heights. In general, transfer structures are the most efficient bearing structures for an office building over railway infrastructure, not only in terms of cost, but also as regards flexibility and safety.

The next chapter will analyse the total investment costs of buildings over railways and will discuss the feasibility of such projects.

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192 Introduction

Chapter 9 Financial appraisal

In the previous chapter, we established the extra cost of the primary bearing structure for an over-track building. The present chapter moves on to consider the financial appraisal of property development over railway infrastructure. It is difficult to make a generally applicable financial appraisal of over-track buildings with special structures – and special technical requirements – because the financial aspect depends so much on local circumstances. This chapter will undertake a financial appraisal by comparing an over-track project with a standard project in an inner-city environment. We shall start by distinguishing the various investment components and establishing their minimum and maximum values, before moving on to discuss the returns on over-track projects. The first element in our appraisal is the investment for a standard reference office building.

9.1 Investment for a standard reference office building

To compare the investment costs for an office building over railway infrastructure with those for a standard office building in an inner-city environment, we first estimated the investment costs for a standard reference office building (referred to hereafter as the reference building). These consist of the investment required to acquire the land and that needed to build on it.

9.1.1 Construction investments References indicate that multi-level offices cost between € 900/m2 and € 1 300/m2 to build [Bouwkosten, 2006]. Analysis of certain Dutch landmark buildings revealed construction costs ranging from about € 1 100 to much higher levels [Heijer, 2002]. Based on these references and on the fact that over-track building will take place in urban areas, the construction costs of the reference building for this study have been estimated (arbitrarily but representatively) at € 1 200/m2. Based on information from Robert Cijs of NS Vastgoed (the property department of the Dutch Railways), additional costs are estimated at 47% of the construction cost, i.e. € 564/m2 (47% of € 1 200/m2). For the purposes of this study,

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the construction costs for the reference building are therefore € 1 764/m2. This figure does not include land costs or VAT. In reference buildings, the costs of a primary bearing structure is € 120/m2, 10% of € 1 200/m2. These costs are similar to the costs presented in Chapter 8 and include the costs for floors and fire-resistant coating for the steel structure.

< Costs for the standard inner-city office 10% building used as a reference in this appraisal [Based oninformation 30% provided by 8% Robert Cijs of NS Vastgoed]

4% 3% 1% 4%

147%

9.1.2 Land investments Land costs vary considerably from one location to another. The value of land comes from what is known as ‘derived demand’: people are willing to pay for land not because of the value that land has of itself, but because land is necessary to obtain other things that have consumption or production value [Geltner & Miller, 2001]. This is known as the ‘residual theory of land value’ and forms the basis for assessing the feasibility of building above the track.

The land costs can be estimated as a percentage of the total investment for new property. The land value is higher in more densely populated areas and lower in less densely populated areas. However, different locations also mean differences in building quality. In high-density areas with a high land value, a developer will invest more, to produce a higher quality building. Conversely, at locations where the land value is lower, investment in office buildings is lower. The land value percentage can be calculated as follows:

Land Value ( € ) Land Value Percentage (%) = Land Value ( € ) + Building Costs ( € )

194 Financial appraisal

References can be used to estimate the land value percentage for office buildings at different locations in the Netherlands. The references are used for a macro-economic comparison between building beside and over railway tracks, a comparison independent of who owns the land beside the tracks or the air rights above. The reference values for land value in station areas have been found in policy documents of Dutch towns and cities. They serve primarily to obtain an overview of the range of land value percentages encountered in practice. Obvi- ously, this range does not constitute the absolute limits. The land values below are all for office development projects. • Helmond: The Municipality of Helmond gives a figure of € 200/m2 of gross floor area developed [Gemeente Helmond, 2005]. Given our assumed construction costs of € 1 764/m2, this equates to a land value percentage of 10% (€ 200 / (€ 200 + € 1 764)). As building costs in Helmond are likely to be lower than for the reference building, the land value percentage will effectively be higher. • Zaandam: For their station redevelopment project, the Municipality of Zaandam indicates a land price of € 350/m2 to € 450/m2 [Dienst Stad, 2002]. With construction costs of € 1 764/m2, this yields a land value percentage of 16% to 20%. Construction costs for town centre offices in Zaandam might be somewhat lower, however, so the true land value percentage could be higher. • Delft: As in Zaandam, a station redevelopment project is underway. The Municipality of Delft quotes a land price of over € 450/m2 for the station area [Gemeente Delft, 2002]. Given the construction costs for the reference office, this is a land value percentage of over 20%. • Leiden: The Municipality of Leiden indicates a land price of up to € 400/m2 in the station area [Leiden, 2004]. Combined with the construction costs for the reference building, this is a land value percentage of about 18%. • The Hague: Land prices near Den Haag Centraal are between € 400/m2 and € 650/m2 [Delft, 2002]. This corresponds to a land value percentage of 18% to 27%. • Amsterdam Zuidas: Amsterdam Zuidas has the highest land prices in Amsterdam. These prices are also far higher than any other city in the Netherlands. The Municipality of Amster- dam indicates a land price of between € 1 089/m2 and € 1 792/m2 [Amsterdam, 2002]. With construction costs of € 1 764/m2, the land value percentage is about 38% to 50%.

Land value < 2005 2002 2002 2004 2002 2002 percentages for different urban areas in the Netherlands

According to Middelkoop, the land value percentage of houses in Amsterdam can be as high as 70%, and there are places in Groningen (in the north of the Netherlands) where it is below 20% [Middelkoop, 2005].

195 256%

192% 202% = € 3 556/m2

building investments Feasibility zone Percentage of standard a building over the railway

Range of investment costs for 111% = € 1 964/m2

100% 101% 99% plus variation in land value = € 1 764/m2 Cost of constructing standard building,

2 4 6 8 10 Number of floors Rail Estate

Land value therefore varies between € 200/m2 and € 1 792/m2 of gross floor area developed. The documents represent different years, but are only spread over a period of three years, so the differences will be marginal. The land value is independent of the number of floors, and is therefore the same for low buildings as for high-rise projects. Construction costs for the building heights 256% to be compared, four and ten storeys, are assumed to be similar; € 1 764/m2. The investment costs for land therefore represent between 11% and 102% of the construction investments for the reference building: between € 200/€ 1 764 192% and € 1 792/€ 1 764.

building investments Range of investment costs As a referencePercentage of standard for over-track property development,for a building over the the development railway rights over the tracks in the Seine Rive Gauche project cost more than the actual construction of the overhead property. A rough calculation based on confidential information provided by Theo Soeters of ING Real 100% 101% 99% Estate= € 1 764/m in2 Paris indicates a land value percentage of 61%. However, one should bear in mind that in the case of Rive Gauche, the cost of the foundation was absorbed by the infrastructure project and the overhead property could be built directly on an artificial ground level. Development rights in London must be even more expensive, but it has not been possible to obtain exact figures. 2 4 6 8 10 9.1.3 Total investment Number of floors As a result of the above, we must add between 11% and 102% to the construction investments for the reference building to obtain the total investment costs for a building located beside the track. This total investment varies between € 1 964/m2 and € 3 556/m2 excluding VAT.

202% < Investment 2 = € 3 556/m costs for the Cost of constructing standard building, reference building; building investments a combination of

Percentage of standard plus variation in land value standard building 111% investments and = € 1 964/m2 100% a variation in = € 1 764/m2 land value

2 4 6 8 10 Number of floors

9.2 Building based on air rights

The concept of air rights originated in the USA. They represent the number of square metres that can be developed on the land one owns. As the heights of buildings in America’s inner cities increased, city authorities introduced regulations to curtail the growth of build-

196 Financial appraisal

ings, mainly to reduce the probability and effects of building fires [New York Department of Building, 2006]. They also introduced regulations to control the speculative growth of the new skyscrapers, where almost the whole site area was used by a vertical building mass, blocking sunlight from the surrounding streets. In effect, New York City has been divided into height districts, and a maximum three-dimensional limit defined for each site, to protect the light and ventilation of adjacent plots. On some undeveloped or underdeveloped sites, these air rights could still be used. Chapter 4 discussed Terminal City over the tracks of Grand Central as an example of an air rights development over railway infrastructure. Terminal City is already over a hundred years old and is the oldest example of air rights development encountered during this study. However, that initial development did not utilise all the air rights. At a later stage of the project there were numerous plans for utilising the unused air rights, finally resulting in construction of the Pan Am Building in 1963. Property development over railways based on air rights is also found in Chicago, with the Gateway Center buildings from the 1960s and the Boeing Headquarters from the 1990s as interesting examples.

In the 1980s, the city authorities introduced a scheme for transferring one building’s air rights (or Transferable Development Rights, TDRs) to another, proposed building [New York Department of Building, 2006]. This was meant to offer an alternative for investors want- ing to demolish old, still functional buildings (‘undersized’ in relation to the total legal height allowed for the site) and replace them with new, taller buildings. The idea was to ‘transfer’ unbuilt building volume to an adjacent plot, enabling the construction of a taller building than the rules would normally allow. For example, the Trump Tower used the air rights of the neighbouring Tiffany & Co. Building [New York Department of Building, 2006]. The market for air rights has been an odd feature of the New York property market for decades. Today, developer brothers William and Arthur Zeckendorf are willing to pay $ 430 a square foot (€ 3 800/m2 at May 2006 rates) for air rights over Park Avenue and East 60th Street. This is more than double the going rate [CNNMoney, 2005].

The area of Grand < Central Terminal before the development of the air rights to turn the area into Terminal City [MTA/Metro- North Collection]

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Transferred FAR < Transfer of development rights Transferred FAR in Tokyo based on Plot floor area ratios Plot Scheme boundary [Paul Chorus]

Unused FAR

Japan also applies the principle of transferable air rights. Tokyo has ‘Urban Planning Areas’, within which land use can be regulated [Chorus, 2006]. These planning areas are divided into categories: residential, commercial and industrial. For all districts, there are regulations concerning the Floor Area Ratio and the Building Coverage Ratio, the latter being the percentage of land that is covered. Air rights are traded from one plot to another and the total amount of property developed must not exceed a fixed maximum.

The UK has also introduced air rights for railway infrastructure; buildings over railway infrastructure are known as ‘air rights buildings’, as building over the railway infrastructure uses the air while leaving the land below for the railway. Plans are still being formulated for building over railways to gain income from the value of these air rights and the example of Liverpool Street Station was discussed in Chapter 4. In the USA, a new air rights development is planned over the sidings of Union Station in Washington [Washington Business Journal, 2002] and the developer of the plan even won a Land Use Award in 2003 for his air rights proposal [Smartgrowth, 2003].

This financial appraisal of building over railway infrastructure will focus on the value of these air rights. The value of the air rights will depend on the difference between the extra cost of the building and the land value of the surrounding area.

There are three possible scenarios: • Building over the track is cheaper than building beside it. The value of the air rights is therefore higher than that of the surrounding land. This scenario is very unlikely. • Building over the track is more expensive than building beside it, but the extra cost does not exceed the value of the surrounding land. The value of the air rights is not as high as that of the surrounding land, but building over the track may still be profitable under this scenario. • Building over the track is more expensive than building beside it, and the extra cost exceeds the value of the surrounding land. The value of the air rights is therefore negative. Under this scenario it is economically more attractive to develop the land beside the tracks.

As the first scenario is unlikely and the third unprofitable, one must find ways of achieving the second.

198 Financial appraisal

9.3 Extra investment costs for over-track construction

The extra investment costs for a building over railway tracks can be placed under a number of headings: • Costs related to the railway infrastructure. These are the costs of preparations to enable the construction of an overhead building. • Costs for the construction of an overhead building. • Costs that result from building over railways in general, such as costs for vibration measures. • Additional costs, such as those related to design, management and risk.

The sum of these four elements is the difference between the investment costs for a building over railway infrastructure and those for the reference building discussed above. Appendix B discusses estimates of the extra cost of building over the track for a four-floor building and a ten-floor building, both for a track-derived structure and for a transfer structure.

General cost < Standard investment costs Extra investment costs comparison Land costs – Air rights between standard Construction costs + Extra costs resulting from changes to railway infrastructure building and + Extra costs resulting from structural design choices building over + Extra costs resulting from building over railways in general railways Additional costs + Extra additional costs Total +/- Total extra cost

At the lowest, the costs of a building over railway tracks will be comparable to those of the reference building. One reference case for such a building is an overhead building over a tunnel. If a tunnel is so constructed that it can bear the load of an overhead building, there will be no costs for the building foundations. However, the savings on the foundations are offset by the more expensive primary bearing structure, be it a track-derived structure or a transfer structure. Real life locations of this type include the Exchange Square in Rijswijk and the future buildings over the tunnels in Amsterdam Zuidas.

In a maximum scenario, the investment costs will be more than two and a half times those of the standard reference building in the case of four floors and about twice as high in the case of a ten-floor building. The variant with ten floors is less expensive per square metre, because part of the extra cost, such as the costs of preparing the railway infrastructure for overhead building, can be spread over a larger number of floors.

A track-derived structure is more expensive than a transfer structure in all cases. This difference stems from the more expensive primary bearing structure and the additional costs for the façade and for building services, as the increased height between floors increases the volume of the building. The spread of the building investments is smaller for higher buildings, as some of the higher costs are independent of the building itself and can therefore be divided over more floor area.

199 256%

192% 202% 2 Rail Estate = € 3 556/m

building investments Feasibility zone Percentage of standard a building over the railway Range of investment costs for 111% < The investment = € 1 964/m2 costs for a building 100% 101% 99% plus variation in land value = € 1 764/m2 over railway tracks

Cost of constructing standard building, compared to the investment for a standard reference building in 2 4 6 8 10 an inner-city Number of floors environment.

256%

192% < Variation in investment costs building investments Range of investment costs for an over-track Percentage of standard for a building over the railway building with a transfer structure. 100% 101% 99% = € 1 764/m2

2 4 6 8 10 Number of floors

9.4 A practical example of determining building investments

The previous section discussed the minimum and maximum extra investment required to build an over-track office building. Because the range is so wide, the question remains of when to consider developing offices over a railway. Some of the extra costs are not particularly high, but are very likely to occur, such as those for vibration measures. Others (such as 202% completely rearranging the tracks) are very high, and projects in which they occur =should € 3 556/m2 be avoided. In this section we shall look atCost how of constructing to determine standard the building, extra costs for a specific virtual building investments

situation. In thisPercentage of standard example, the tracks are atplus ground variation inlevel. land value 111% = € 1 964/m2 We shall100% use a transfer structure for the cost estimate, as this is less expensive than a = € 1 764/m2 track-derived structure. We shall also use an office building with ten floors rather than four, as some of the costs can be divided over a larger gross floor area. It is also assumed that the construction site costs will not be more than twice those of a normal site, which is a very different assumption from that2 made in4 the maximum6 cost scenario. 8 10 Number of floors

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A virtual reference < 7.2 7.2 7.2 building over ground-level railway tracks. 3.6 7.2 3.6 3.6 7.2 3.6 3.6 7.2 3.6 3.6 7.2 3.6 3.6 7.2 3.6 7.2

21.6 21.6

The aim of this cost estimate is to show how the extra costs of a virtual situation compare with the minimum and maximum scenarios in the previous section. It also illustrates how the cost estimates in Appendix B can be used in practice. The references for the cost estimate all appear in Appendix B.

The example is imaginary, but it does show that the extra investment costs for the building can be limited (to about 35% in this case) if it is possible to avoid such high-cost items as changes to the railway infrastructure. An extra investment of 35% is still a high percentage, and there are few locations in the Netherlands where the land value is that high (as we saw in 9.2). Nevertheless, specific value engineering on the investments required for building over railway tracks can substantially reduce total investment costs.

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Building [6 221 m2 ] Extra costs [€/m2 ] Total < Costs for the standard inner city office building used as a reference in this appraisal [Based on information provided by Robert Cijs of NS Vastgoed]

9.5 Financial risks

Independently of the extra costs estimated above, there are financial risks inherent in building over railway tracks that have to be taken into account. It is difficult to incorporate these risks into cost estimates, because they mainly depend on the process (including the political aspects) that governs the project.

9.5.1 Building time The complexity of building time is a general risk inherent to building over railways. However, a specific financial risk emerges when third parties are involved. Unforseeable extended building time is a financial risk that should be taken into account. During construction of Lehrter

202 Financial appraisal

Bahnhof in Berlin, part of the structure was still not complete when trains started using the new station. More than 100 m of glass roof remained unfinished and are still waiting in a depot to be installed … one day. Compensation and lawyers’ fees can rise quickly during complex construction projects, as happened in this case. The financial consequences of a longer building period can be substantial.

The extended building time can cause a secondary problem; more nuisance to the surroundings compared to a standard inner-city office development project. This leads to public costs, albeit not necessarily in euro.

9.5.2 Pre-investment By pre-investment, we mean here such measures as placing foundations or columns between the tracks to take the load of a future building. Measures of this type can reduce building time at some point in the future, by providing foundations that will allow the placing of prefabricated over-track structures. The costs of such pre-investment can be reduced significantly if it is made when the tracks are taken out of service for maintenance or other railway-related reasons.

However, there are two major risks related to pre-investment: time and use. If construction takes place much later, the interest paid on the pre-investment will be so high that higher investment at a later stage would have been cheaper overall. Another problem is that the pre-investment measures might not match the structure of the overhead building actually constructed. In such a case, the pre-investment may be more of a hindrance than a help. And it might never be used, or used much later. Rotterdam Blaak Station, for instance, includes pre-investment in the form of a structure for future overhead buildings. This investment was made in the early 1990s but is still unused. So pre-investment forms a financial risk, despite being intended to diminish total project costs.

9.5.3 Legal issues Building over infrastructure brings legal complications. Civil and tax law both treat building over railway tracks the same as building over roads [Breedveld, 2002]. Problems include property rights in connection with the building and the land, plus the issue of liability. Given the fact that the railway owner sees the railway as a single piece of property combined with the land, the owner of the new building above will not be the owner of the land below and will have no influence on the use of that land. This ownership situation is not recorded in the property register [Stoter & Ploeger, 2003]. For future owners, all rights and obliga- tions regarding the use and maintenance of the building must be transferred and obliga- tions must be clear. They also depend on the way in which the use and maintenance of the railway tracks are organised.

9.5.4 Tax issues The sale of existing property is subject to a property transfer tax of 6%. When building land or a new building is sold after development, VAT is charged [Blommers & Paardt, 2002], but the developer is granted a property tax exemption to avoid double taxation. In the Netherlands, the VAT rate is 19%.

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Building over existing infrastructure creates a new phenomenon; for legal reasons, building rights are transferred for the use of the space above the infrastructure. These building rights are also subject to property transfer tax but, as the infrastructure is not new, there is no VAT [Braakman & Zwan, 2001]. Since the developer does not have to pay VAT, he will have to pay property transfer tax instead. Unlike VAT, property transfer tax is not deductible. As a result, the land cost is 6% higher than in the case of buildings on ‘normal’ land. This is in conflict with the social need to stimulate multiple use of space [Breedveld, 2002].

9.5.5 Insurance issues There is a risk of the infrastructure and the building over it affecting each other. One risk is that the building collapses onto the tracks and puts them out of use for an extended period. The cost of a line being out of service is very high, so the risk must be insured. This forms an important financial risk, even if it is possible to insure the building. Liability is also an important issue, and one which also affects the maintenance of the building and the railway. The plans to build over the Rotterdam Willemspoortunnel have already been delayed for many years, mainly because of risk and insurance issues.

9.6 Benefits of building over railway tracks

The benefits of building over railway tracks can be compared to those that accrue from other inner-city projects. The direct financial benefits of building over the track are determined by the rent and the gross initial yield, assuming that the over-track building and the reference building are of the same quality in terms of finishing and use. However, there is little or no information concerning the difference in rent and gross initial yield between property beside and over infrastructure. A number of Dutch property specialists were therefore interviewed to gather such knowledge as is available (Appendix C). There are also a number of indirect benefits that one should take into account when assessing the feasibility of over-track construction. These include subsidies, better use of public transport, increase in the land value of surrounding areas and project benefits over a larger area. The interviews also covered these indirect benefits.

Type of benefit Variation in benefits < Comparison of benefits between standard property and property over railways

9.6.1 Rents The environment of the city centre means that rents are usually higher than at other locations. When buildings over railway infrastructure in an inner-city environment are compared to other buildings in an inner-city environment, experts indicate that the over-track location does not automatically generate a higher rent. In the Netherlands, there are three locations

204 Equinox, over the Utrechtsebaan motorway in

The Hague 2 <

(€ 226/m per year) Property < development over the A10 ring road in Amsterdam 2 (€ 185/m per year)

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where buildings over infrastructure can be compared to buildings in their immediate vicinity, because the rents are known: Rijswijk, The Hague and Amsterdam. The figures were obtained from estate agents Jones Lang LaSalle and DTZ Zadelhoff [Jones Land LaSalle, 2005; interview Bart Louw 6 July 2005]. This study compares rents in a building over infrastructure, rents in a building nearby and the average rent in the city. The buildings used for comparison were selected on the basis of postcode.

In Rijswijk, an office building named Traffic Square has been built over the new station. The comparison building is Hoogvoorde. Rents are € 160/m2 per year in Traffic Square and € 147/m2 per year in Hoogvoorde [Jones Lang LaSalle, 2005].

The Equinox building over the Utrechtsebaan (a local road in The Hague) was completed in 2000. The comparison building, De Monarch, was completed in 2005. Equinox has a rent of € 226/m2 per year while space in De Monarch costs € 209/m2 per year [Jones Lang LaSalle, 2005]. Although the difference is substantial, it seems to be explained by the fact that Equinox only has about 500 m2 available of its 9 700 m2 total, while De Monarch has much more of its 75 000 m2 available.

The Bruggebouw Noord was built over the A10 ring road in Amsterdam. The comparison building is the nearby Orly Plaza. Both Bruggebouw Noord and Orly Plaza have rents of € 185/m2 per year [Jones Lang LaSalle, 2005].

The results of the rough comparison study above were also compared with average rents in the cities concerned. The aim of this second comparison was to estimate whether such over-infrastructure buildings are in their respective cities’ prime locations. Average rents for each city are derived from property transaction information in the database of DTZ Zadelhoff

< Comparison between rent for property above infrastructure, rent beside infrastructure and average rent in the town or city concerned [Jones Lang LaSalle, 2005 & Louw, 2005]

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[Louw, 2005]. The information dates from 2004 and 2005, and the individual figures are confidential. The average rent per square metre was determined by multiplying the number of square metres within an individual transaction by the rent per square metre of that transaction. The sum of these transactions was divided by the total number of square metres of all objects.

The results show that in two cases the rent for property over infrastructure is higher than for other property nearby. This would appear to be due more to local circumstances than to these objects being located over infrastructure. Unfortunately, the number of projects that can be compared is limited. Experts indicated without exception that the rent level of a building over infrastructure is not expected to be higher than a building beside it. It seems reasonable to expect the rents for property over infrastructure to be similar to those of nearby property. The figures also show that projects over infrastructure are not always sited at prime locations. The rent for the building over the A10 ring road in Amsterdam is in fact lower than the average for Amsterdam. The property specialists interviewed for this study came to a similar conclusion without these figures – the rent on property over infrastructure is no higher than that for property beside it. More interestingly, it may even be lower. Factors mentioned by the specialists as possibly lowering rent are as follows: • A less attractive entrance to the building at ground level. A building over railway infrastructure must be easily accessible. An office building also needs an address at street level. It might be difficult to create an attractive and accessible entrance to an over-track building, and an unsatisfactory entrance has a negative effect on the rent. • Accessibility and parking. Car access to the area is very poor in many cases. Further- more, creating parking space for a building over railway infrastructure is difficult, as an underground car park under railway tracks is expensive. Parking spaces above the track are difficult to reach and will also be expensive. Parking space must therefore be found beside the track, near to the office buildings. Although parking places can be obtained at market rates, the distance to the new office over the railway infrastructure is a problem, nor can one expect to find attractive amounts of parking space. • A window view over the railway infrastructure. A view over railway tracks can have a negative effect on the rent of a building. • Market conditions. The typical market for station locations consists of back-office buildings for insurance companies and banks. There is also a large market for non-profit organisations, such as foundations and government. This segment of the market does not pay the highest rents.

The factors described above must be taken into account when conducting a feasibility study for an over-track building. If they are not, the rent may be much lower than in the surrounding area because of the possible drawbacks of railway infrastructure. Unlike a building over road infrastructure, a building over railway infrastructure is not a high-visibility location. A person in a car looks forwards, so a building over the road will be visible to him. A train passenger looks out of the side, and hence will not see buildings over the track.

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9.6.2 Gross initial yield The value of property is determined not only by the rent that can be charged but also by the gross initial yield. As in the case of rent, property specialists point out that the gross initial yield is no more favourable for a building over railway infrastructure than for one beside it, and might very well be less so. The factors that influence the gross initial yield negatively are as follows: • Maintenance costs: Maintenance costs will be higher for a building over the track than for a normal building. If the building is not well-designed in this respect, maintenance will require interruptions to railway operations. That will incur additional costs. And even if it is possible to carry out regular maintenance without such disruption, the underside of the building and the columns are extra items to maintain. • Renovation costs: Renovating the building will be more expensive because of its location over the track. The gross initial yield will reflect these higher renovation costs, because future costs will be higher. • Property management: Property management may be more complex – and hence more expensive – due to the infrastructure below. Use of the building must be compatible with use of the tracks underneath it. The running costs of the building will be higher, influencing gross initial yield negatively. • Lack of full ownership: Although the air rights are used, the owner of an over-track building does not fully own the land. The fact that an investor cannot obtain full ownership of the building and the land on which it is built is a drawback, especially for foreign investors. This drawback will be reflected in the appraisal of the building and therefore also in the gross initial yield. • Uncertainty: The fact that another organisation manages the railway tracks under the new building is an uncertainty for an investor. Because the railway infrastructure is a national investment, of which the interests go beyond the interests of the owners of individual buildings above it, there will be uncertainty regarding the use and saleability of the building. This will also influence gross initial yield negatively. • Insurability: The risks that railway infrastructure imply for overhead property make it more expensive to insure the building. The premium will be higher than normal. When accidents occur (even at other locations), premiums will rise, which is a risk factor in the running costs of the building.

However, the fact that a building is located over the track may also have a positive effect on gross initial yield: • Flagship project: Projects that involve building over railway tracks are usually unique, and may serve as flagship projects for a developer. As a consequence, a developer might choose to build property with a lower return on investment, simply because the project boosts his image. When other developers start creating such projects a ‘me too’ effect can arise. However, only very large developers can choose to operate in this fashion, as the risks are high. It is highly unlikely that investors will want to invest in flagship projects of this nature. • Economic lifespan: One advantage of buildings in station areas is that they are occupied by a series of users. Only limited alterations to the building are required to attract new tenants. Property in station areas therefore has a longer economic life than that in business parks.

208 Financial appraisal

• Lower vacancy rates in station areas: Because many back-offices of banks and insurance companies, governmental organisations and non-profit organisations are located in station areas, it is easier to find a tenant for the office space. As a consequence, the vacancy rates in station areas are generally lower than elsewhere.

The last two advantages also apply to station areas in general.

9.6.3 Subsidies Subsidies on over-track property constitute a valuable benefit for developers. Because such property contributes to urban quality, social safety, utilisation of space and public transport – and even to the image of the city – it is possible to offer various forms of subsidy. These subsidies may be direct or indirect, such as putting the air rights at a developer’s disposal free of charge. Subsidies were available for the project over the Utrechtsebaan motorway in The Hague and the Bruggebouw Noord over the A10 ring road in Amsterdam. Obviously, these subsidies only benefit the developer, not society as a whole.

9.6.4 Utilisation of public transport New building increases traffic to and from the station. On average, more people will use public transport, and public transport operators can make more profits when the existing infrastructure is used more efficiently. Station shops will see increased sales because of the larger number of passengers. These advantages should make railway-related companies willing to invest in the development of station areas in general. Furthermore, such benefits accrue not just to one single building over the railway infrastructure, but to the station area as a whole.

9.6.5 Land value of surrounding areas In many cases, property above the track is part of a larger development scheme, in which the extra costs of building over the railway can be spread over a larger number of square metres of property developed. When the redevelopment is indeed part of a larger scheme, ways must be found of offsetting costs and possibilities must be used to settle part of the costs. For the Zuidas project, it is estimated that building the Dock Model will lead to an increase in property value of 10% for existing and future property [CPB, 2003]. A 10% increase in property value for a whole area is a very substantial benefit. However, it is not certain that over-track property will cause land values to increase by more than if the same urban development had been undertaken without it.

Other research shows that the value of surrounding premises increases when new property is developed [Bowes, 2001]. Logically, over-track buildings should also have this effect, especially because they diminish the negative effects of railway infrastructure, environmental and otherwise. Higher property values (and hence land values) around the station are a source of income for both local and central government. Local government levies property tax on the basis of property value; if the value rises, so does the local property tax income. Central government levies a property transfer tax when property is sold. In the Netherlands, the property transfer tax is 6%, which can yield quite substantial sums in areas with high land values.

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Existing owners of property in station areas also benefit from rising property values. How- ever, it is difficult to ensure that these benefits in any way accrue to the project itself. Hertog and Marlet argue that in the Dutch situation existing owners are compensated for the damage brought about by new large-scale projects. It should therefore be possible to negotiate a special zone levy to finance these station redevelopment projects [Hertog & Marlet, 1998]. Such a levy could also be used to finance over-track urban development.

9.6.6 Project benefits over a larger area The costs and benefits of urban development in station areas can be combined. Projects beside the tracks can be used to finance those above, certainly in the case of larger-scale projects. The costs and benefits can be reflected in a Masterplan or a station area development corporation. A partnership of this nature was created for the King’s Cross Railway Lands [Bertolini & Spit, 1998]. It is also possible to spread the costs and benefits associated with buildings that are partly constructed over railway infrastructure, but this depends on the relative areas built beside and above the tracks.

9.7 Feasibility of building over railway infrastructure

Air rights have a positive value when the extra costs of property development are less than the residual land value of the surrounding area. In that case, the value of the air rights will lie between zero and the residual land value of the surrounding area, as discussed in 9.1.2. As we saw in that subsection, land value in the Netherlands is equal to between 11% and 102% of the construction costs of the reference building. The total investment for the reference building will therefore be between 111% and 202% of the construction cost, excluding VAT. The extra cost of a transfer structure lies between 1% and 156% for a four-floor building and between -1% and 92% for a ten-floor building. These figures can be compared to the land value, and the result is a zone in which air rights have a positive value.

256%

192% 202% < The feasibility zone 3 556/m2 = € for building over railway tracks with

building investments Feasibility zone

Percentage of standard a transfer a building over the railway structure; a Range of investment costs for 111% = € 1 964/m2 positive value of

100% 101% 99% plus variation in land value the air rights = € 1 764/m2 Cost of constructing standard building,

2 4 6 8 10 Number of floors 210

256%

192%

building investments Range of investment costs Percentage of standard for a building over the railway

100% 101% 99% = € 1 764/m2

2 4 6 8 10 Number of floors

202% = € 3 556/m2

Cost of constructing standard building, building investments

Percentage of standard plus variation in land value

111% = € 1 964/m2 100% = € 1 764/m2

2 4 6 8 10 Number of floors Financial appraisal

When determining the feasibility zone, it is assumed that the rent and the gross initial yield of property over the track are similar to those of property beside it. The possible extra benefits discussed in 9.6 have not been taken into account, because it is not possible to predict the magnitude of such benefits. Indeed, whether or not they will accrue at all depends on the specific circumstances. If they do apply, they can increase the value of the air rights.

At present, property development is generally considered at those locations with the highest rents, as these locations can generate the highest contribution to feasibility by including the land value in the project. Examples include Amsterdam Centraal and Utrecht Centraal. However, locations with the highest rent value often have the highest complexity in terms of physical safety and railway logistics. The higher complexity of these locations might very well increase investment costs to a disproportionate degree, making projects at such locations uneconomic. As a consequence, the general opinion is that if such projects are not feasible at such high rent levels, there is no point in even considering other projects. However, given the nature of the extra costs for building over railway infrastructure, it might be more rewarding to look at suburban stations and stations at other strategic locations, where the technical constraints are less severe and the rent levels are not that much lower than in the inner-city areas. This might pave the way for a new and larger group of possible locations for building over railway infrastructure.

9.8 Conclusion

The difference between the value of the surrounding land and the extra cost of developing an overhead building will determine the feasibility of building over railway infrastructure. This difference can be defined as the value of the air rights over the railway infrastructure.

For the purposes of this study, we have looked at a standard office building with a construction cost of € 1 200/m2. With an additional cost percentage of 47%, the building investment is € 1 764/m2. The extra cost of building over railways and of surrounding land values will be a percentage of these investment costs. Research on land value percentages in the Netherlands showed a broad variation: between 11% and 102% of the building investment. 17% is a very low percentage, encountered in smaller towns in less densely-populated parts of the country, while 102% is the highest land value encountered, quoted by the Municipality of Amsterdam for the Zuidas project.

The estimation revealed the construction costs for building over railway tracks to be significantly higher than those for the reference building elsewhere, both for the transfer structure and for the track-derived structure. The extra cost of building over the track can be divided into extra railway-related costs, extra structure-related costs, extra general costs for building over railways and extra additional costs. The construction costs for the over-track buildings studied ranged from 99% to 270% of the reference building investment. The transfer structure was less expensive than the track-derived structure in all situations, and the ten-floor building was less expensive than the four-floor building, per square metre of gross floor area. The variation between minimum and maximum extra construction

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costs is very wide. An average reference situation for over-track property development was also discussed to indicate the savings possible when choosing a strategic location for an overhead building. This virtual reference building of ten floors with a transfer structure and railway tracks at ground level required an extra investment of 35% compared to the reference building.

Research shows there to be little difference in benefits between property over the track and property alongside. Rent and gross initial yield are virtually the same for both. If an over-track building is designed properly, it should be possible to match both the rent and the gross initial yield of property beside the track. Certain factors can have a negative influence on the rent and gross initial yield of over-track buildings. There are some indirect benefits from building over the track, but it has not been possible to express these in general monetary terms, as they depend too much on local circumstances.

212 Introduction

Chapter 10 Conclusions and recommendations

This chapter will conclude the wide range of research subjects discussed in connection with property development over and near railway infrastructure. The chapter will start with the main findings and conclusions of the research, followed by discussion of the feasibility of these projects in general and the contribution of this research to the field of work. The chapter will finish with recommendations, both for further research and concerning general policy for such projects.

10.1 Main findings and conclusions

The aim of this research was to gain a better understanding of property development over railway infrastructure. The scope was limited to the technical and financial aspects, but included all relevant topics within those areas. The result is an overview that can be used by policy makers, property developers, investors, designers and other parties involved in this new way of using urban space, one that is rapidly developing into an instrument for optimising the use of space and redeveloping station areas.

10.1.1 Use of space and railway infrastructure Over the last 50 years, urban growth has been based on an increase in wealth that has made individual transport by car available to the masses. However, this increased mobility has led to mono-functional, low-density sprawl. Congestion and the loss of countryside are motivating a search for ways to limit the expansion of cities. New space must preferably be found within city boundaries, and this leads to projects involving multiple and intensive use of space. By multiple use of space we mean the combination of different functions within a certain space, whereas intensive use of space can be defined as denser occupation, which is possible in all dimensions. In practice, multiple and intensive use of space are often combined. Strategies for optimising the use of space by making multiple and intensive use of it can involve the second (surface), third (height) and fourth (time) dimensions, and all

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combinations are possible. These strategies are applicable at different scale levels, such as floor, building and urban district.

More efficient use of urban space is prompting renewed interest in public transport as a means of solving the problem of congestion. In turn, this is leading to more intensive use of railway infrastructure. Compared to other railways in Europe, the Dutch network is used very intensively, leading to stringent capacity and availability requirements. These impose severe constraints on overhead construction.

The options for building in station areas – and specifically for building over track – depend on the station type. For the purposes of this study, station typology is defined by the functional arrangement of the station (terminus station, through station or cross station) and the vertical position of its track (underground, subsurface, ground level or elevated).

10.1.2 Reference projects outside the Netherlands A review of the European situation reveals the existence of many interesting projects involving property development over railway infrastructure. A survey of the available literature showed that there has so far been no in-depth study of multiple and intensive use of space, focused on projects involving building over the track. Six reference projects were studied and compared, prompting a number of interesting conclusions.

Similarities: The similarities are a comparable use of space, a comparable urban density in terms of the floor space index, and a general trend towards a more diversified mixture of functions. Furthermore, most projects are linked to the integration of the high-speed train and in most cases are the result of the planning process for it. However, the main factors determining the success of the reference projects are not the integration of the high speed train itself, but local context, local developments and – in particular – a successful first phase.

Differences: Most differences stem from the fact that projects were conducted in different countries rather than from any differences between the buildings themselves. Property development over railway infrastructure started in London in the 1980s, to be followed by Paris in the early 1990s. Germany and the Netherlands joined in during the second half of the 1990s. In London, development is initiated and mostly carried out by private bodies, whereas in France it is generally government bodies that play this role. A combination of private and public bodies is the norm in Germany and the Netherlands.

Another difference is the rent that can be charged. Higher rents make building over tracks more feasible. Office rents in London are very high, so private parties can develop these projects on their own. Rents are lower in Paris but still high enough for the public bodies to run the development themselves. Rents in Germany and the Netherlands are substantially lower and public and private parties need to join forces in partnerships, which leads to long and complex processes to make the project feasible. Feasibility also depends on the extent to which government bodies are willing to pay for the unprofitable part of the project.

214 Conclusions and recommendations

There are also differences in urban design. Many inner-city railway areas do not allow high-rise buildings because of historic city views. In these projects, intensive use of space is achieved by occupying a high percentage of the land surface. Structural solutions also differ; in London, steel is used for over-track structures, whereas projects in Paris use concrete.

The Dutch context: Study of the reference projects also highlighted specific points regarding the Dutch situation. In the Netherlands, lack of space is a countrywide problem, not an inner-city one. This does not help to make building over track profitable, as land values in cities are relatively low. Furthermore, almost all Dutch stations are of the ‘through’ type, which are more difficult to build over, as the tracks are more intensively used and in most cases hazardous goods pass through these stations.

10.1.3 Design requirements Research into technical requirements focused on three aspects. The first was quality and flexibility, seen as the ‘softer’ design requirements. The second was noise, vibration and electromagnetic compatibility, seen as the ‘harder’ requirements. Finally, physical safety was examined separately because of its specific importance.

Quality and flexibility: Research on quality and flexibility gives an insight into the ‘softer’ requirements regarding the design of over-track buildings. Quality is needed to create a pleasant and crime-free space, while flexibility is needed to enable adaptation to changing requirements. One can compare building over railway infrastructure with building underground. Quality and flexibility can be examined for both the railway infrastructure and the surrounding city. Trans- port quality is negatively influenced by building over the platform areas, as the new structure blocks out daylight. Creating spatial quality in the platform area involves retaining sufficient headroom, establishing a balanced combination of daylight and artificial lighting and adapting the finishing of the platform area to an indoor environment. The quality of built-over Dutch platforms is very poor compared to projects abroad, while at the same time quality here is even more important because the platform area also functions as an accommodation space. The examples abroad are mainly terminus stations where platforms only function as a transfer space, and yet they offer a higher standard.

Public space can be divided into transfer space and accommodation space. Transfer space should be accessible and conveniently arranged, while accommodation space should be finished to a high standard. Urban quality is also influenced by the quality of the connections with the station and by the finish of surrounding property.

Four types of flexibility were defined: changeability, extendibility, maintainability and phase- ability. Changeability means being able to change the railway infrastructure or the overhead buildings. Extendibility is the possibility of extending the infrastructure, for instance by adding new platforms and tracks, or of extending the urban environment. Maintainability is needed to enable maintenance on the infrastructure with minimal influence on its availability, and to enable maintenance on the overhead building with no influence on the availability of the railway infrastructure. The last aspect of flexibility is phase-ability. Because projects involving redevelopment of station areas can easily take up to 20 years, the design should make it

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possible to change plans after each phase of execution. Phase-ability can make it possible to change the railway infrastructure in different phases, while keeping that infrastructure available at all times. Taking quality into account at every stage will limit the effects of any delays to the project on the functioning of the new station area. The flexibility and quality of both the infrastructure and the surrounding city can be weighed against each other. Transport flexibility, transport quality, urban flexibility and urban quality are all related, and these relationships can be positive or negative.

Technical aspects: Technical aspects determine the boundary conditions for the design of buildings over and near railway tracks. There are three important technical aspects: noise, vibration and electromagnetic compatibility (EMC). The link between noise, vibration and EMC lies in the fact that they all have a source, a transmission path and a recipient that can be analysed and modified by means of convenient and cost-effective measures. It is interesting to note that one difference between property development projects over railway infrastructure and those alongside the track is that the vertical noise emission of trains is lower than the horizontal noise emission. It is possible to take measures against noise nuisance at the source (e.g. rail dampers), along the transmission path (noise screens) and at the recipient (having no opening windows in the wall nearest the track, as a last resort). Vibration poses a bigger challenge. The transmission of vibration through soil and structure is difficult to predict and it is difficult to decide which range of frequencies to take into account when designing the structure, as different types of train have different excitation frequencies. The present study proposes a set of measures that should be considered carefully in the light of the local situation. When a large number of buildings are located near the track, measures at the source are cost-effective. Where there are fewer buildings, measures should preferably be taken at the recipient or alternatively along the transmission path. EMC is another area in which it is difficult to predict the effects. It is difficult to establish the correlation between the effects of low-frequency, medium-frequency and high-frequency electric and magnetic fields, and countermeasures have limited effect. It is easier to achieve EMC if one takes this aspect into account at an early stage in the design process. Technical measures include using LCD screens or a Faraday cage, although the latter is only effective for electric fields. One functional measure is to modify the building layout. Research on these three aspects has shown that it is not possible to specify a generally-applicable package of technical measures when building over and near railway infrastructure, as local factors predominate.

Physical safety: Physical safety is one of the most important problem areas affecting construction over and near railways. In the Netherlands, the main factor is the transport of hazardous goods through many stations. The rules and regulations related to the associated risks are incomplete and unclear. Building over railway infrastructure requires external safety risk analyses that address the following risks: • The risk that railway infrastructure poses to over-track buildings. • The risk that over-track buildings pose to railway infrastructure. • The risks related to the construction and maintenance of over-track buildings

In addition, a risk analysis of the internal safety of the railway infrastructure is required when large sections of railway infrastructure are built over.

216 Conclusions and recommendations

Analysis of the rules and regulations concerning safety revealed some important blind spots that need to be filled in to make an appropriate risk analysis of building over and near railways. Firstly, regulations need to make more room for taking safety measures along the risk transmission path and at the property which is at risk, instead of only at the source. Secondly, it is essential to include the third dimension in normal risk analysis methods used before moving on to complex quantitative risk analyses. Thirdly, the use of one contour for all types of accident is too coarse and hence not always appropriate, because different risks have different probabilities and different effect distances. One option would be to abandon the line infrastructure contour for individual risk. Finally, it is of the utmost importance that the spatial context be included in risk analyses.

The above observations have been translated into a new external safety concept, the HR-3D method, which provides a means of enabling existing computer models to differentiate more precisely. The method was used in practice for three urban development projects, each at a different scale. HR-3D provides ways of reducing both individual and societal risk and constitutes a useful intermediate step between generally accepted risk calculation models and quantitative risk analyses for projects involving multiple and intensive use of space, handling various types of accident, various effects and various measures in a differentiated fashion.

10.1.4 Structural design Designing over-track structures involves stacking different grids. Railway infrastructure gives four possible generic locations, but there is no generally applicable length for the span of the over-track structure. In the Netherlands, buildings use three standard grids: 5.40 m, 6.00 m and 7.20 m. These can be used at all locations and can also be mixed.

There are three types of structure that can be used for building over railway infrastructure: the track-derived structure, the transfer structure and the mega transfer structure. The track-derived structure follows exactly the grid that the railway imposes on it. The transfer structure is an intermediate layer that converts the unfavourable grid of the railway into a grid favourable for over-track building. The mega transfer structure is a specific type of transfer structure of which the height of the structure is more than half the building height. It also has a convenient grid for the buildings it carries.

The track-derived structure has the advantage that it has a limited height when it is used for one floor, such as an artificial ground level over the track, and that it gives more freedom in the functional arrangement of the floors. Transfer structures increase the flexibility of the over-track buildings and, to some extent, that of the track. They can also enhance physical safety, as it is easier to design the building structure on the transfer structure to prevent progressive collapse. Mega transfer structures can increase the flexibility of the track and possibly the quality of the building, as such structures usually function as landmarks.

A basic structural design was produced for the track-derived structure and the transfer structure in order to compare the costs of the two. The basic structural design involved specific challenges regarding the stability of the structure, the foundations, the connection with the surroundings at street level and the construction process. The costs of the structures were

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also compared. The structure for a building with a track-derived structure is more expensive than that for a building with a transfer structure, in all situations. For short spans (up to 15 m) the costs are comparable, but for longer spans the track-derived structure required for all floors is far more expensive than a building with a transfer structure. The construction costs were compared to those of a standard reference office building, estimated at € 120/m2. A four-floor office building with a track-derived structure is roughly 50% – 160% more expensive than the reference building and a ten-floor building is 40% – 140% more expensive. A four-floor building with a transfer structure is roughly 40% – 100% more expensive and a ten-floor building 20% – 70% more expensive than the reference building. A transfer structure is cost-effective when the building has more floors, as the costs of the transfer structure can be spread over more square metres of gross floor area. More floors do not make a track-derived structure much more cost effective, as every floor is a track-derived structure. In general, transfer structures are the most efficient bearing structure for an office building over railway infrastructure, not only on cost, but also in terms of flexibility and safety.

10.1.5 Financial aspects The difference between the residual value of the surrounding land and the extra cost of developing the overhead building will determine the value of the air rights above railway infrastructure. Property development over railway infrastructure can be feasible if the value of the air rights is positive. In the Netherlands, land value varies between approximately 11% and 102% of the construction costs. For the purposes of this study, the investment costs for an over-track building were set at € 1 764/m2, made up of € 1 200/m2 of construction costs and 47% additional costs (€ 564/m2). The extra costs for building over railways can be divided into extra railway-related costs, extra costs related to the structure chosen, extra general costs for building over railways and extra additional costs. The total investment costs for all over-track buildings studied varied between 99% and 270% of the construction cost of € 1 764/m2. An example for a theoretical location gives more insight into how often the various extra costs actually arise and ways of controlling them. It also indicates how to use the cost estimates in Appendix B.

Research on the financial benefits shows that rent and gross initial yield are virtually the same for over-track property and property beside the track. There are, however, certain factors that can influence these elements negatively. There are also potential indirect benefits, but it is not possible to express these in figures because they depend too much on the local situation and on political decisions. When direct benefits are estimated to be equal to those from normal buildings beside the track, there is a feasibility zone for building over-track. This zone is that in which the extra investment costs are lower than the value of the surrounding land. The financial appraisal takes no account of possible indirect benefits, including indirect public benefits, and these could also have a positive effect on feasibility.

10.1.6 The feasibility of building over railway infrastructure The feasibility of property development over railway infrastructure has been one of the central questions in this research. Having established the technical boundaries of the project and the specific measures that need to be taken, one must ensure that it will have a positive financial result, direct or indirect.

218 Conclusions and recommendations

As possible locations for building over railway infrastructure differ widely in their technical and financial constraints, there is no global answer to the question of feasibility. Every project will require a specific financial analysis to produce a development plan. What the research has shown is that it is possible to draw up a general list of the costs that can arise. When one has the figures for all these elements, it should be possible to estimate costs to within a limited range, with a degree of precision similar to that of a preliminary design. It is also possible to make a rough estimate of the returns, as expert opinions and a limited number of available examples indicate that the direct returns on property over railway infrastructure are comparable to those on property beside the track.

With the estimation of the investment costs and the direct returns at hand, the feasibility of the project depends on the way in which the value of the air rights is taken into account, compared to the value of the land beside the track. In essence, the project is feasible when the extra construction investments compared to those of the reference building are no higher than the value of the land beside the track. This means that the value of the air rights must not be less than zero for the project to be feasible. But even if it is, direct and indirect subsidies can possibly make up the difference.

At present, property development is generally considered at those locations with the highest rents, as these locations can generate the highest contribution to feasibility by including the land value in the project. Examples include Amsterdam Centraal and Utrecht Centraal. However, locations with the highest rent value often have the highest complexity in terms of physical safety and railway logistics. The higher complexity of these locations might very well increase investment costs to a disproportionate degree, making projects at such locations uneconomic. As a consequence, the general opinion is that if such projects are not feasible at such high rent levels, there is no point in even considering other projects. However, given the nature of the extra costs for building over railway infrastructure, it might be more rewarding to look at suburban stations and stations at other strategic locations, where the technical constraints are less severe and the rent levels are not that much lower than in the inner-city areas. This might pave the way for a new and larger group of possible locations for building over railway infrastructure.

10.2 Contribution to the field of work

This research was deliberately designed to cover a wide range of technical and financial aspects. Besides conducting scientific research, the study aimed to develop a comprehensive overview of available and new knowledge regarding property development over railway infrastructure that could be used in practice. The main objective is therefore to cover all relevant technical and financial aspects of property development over and near railway infrastructure in one study for the first time. Within this overview, four subjects constitute steps in the advancement of knowledge in this field.

The first is the work on reference projects abroad. None of the existing work examines and compares the spatial and technical aspects of reference projects outside the Netherlands that involve over-track property. The present research on these reference projects provided

219 Rail Estate

information on the similarities and differences between different countries and made it possible to draw conclusions for Dutch practice.

New insights were also obtained in the field of external safety. The transport of hazardous goods through many inner-city locations where building is planned over and near railway infrastructure poses considerable challenges. As available regulations and related computer models to calculate the level of safety have not been developed with multiple and intensive use of space in mind, policy makers and designers of such projects are confronted with incomplete instruments for developing a physically and socially safe environment. The HR-3D method that was developed as part of this research has shown its value in different projects in practice by yielding a more differentiated and spatial interpretation that reflects the intention of legal instruments.

The third area in which this research constitutes a new step is the development of concepts for bearing structures over railways, including a comprehensive comparison of technical aspects and the associated construction investment. Chapter 8 classifies the different structural solutions into three basic types, comparing them on the basis of the technical requirements established in Chapters 5 to 7. The different structures have been calculated in such a way that their costs can be compared.

The last subject that forms a new contribution to the field is a comprehensive comparison between the investment costs of building over railway infrastructure and those of building in a normal inner-city environment. The comprehensive overview and estimation of cost elements provides tools for determining the investment costs of building over the track at any location. Furthermore, a first step has been made in determining the direct returns on these projects. With no literature available, except for general research on station areas, expert opinions and examples from practice show no difference in rent levels or gross initial yield for over-track buildings. The value of air rights can be derived from the difference between the residual land value beside the tracks and the extra costs of building over it. This may be a new way of approaching these projects.

10.3 Recommendations

Researching a subject as broad as the technical and financial aspects of property development over railway infrastructure reveals numerous opportunities for further research. This section proposes directions for further research on the subjects discussed. In addition, research is recommended on government policy regarding the development of multiple use of space in station areas.

Reference projects • This research involved examining a number of projects outside the Netherlands, studying their origins, their use of space and the structural solutions adopted for building over the railway. Further research on the financing of these projects could be interesting. The present study did not establish the costs that these projects incurred for changes to railway infrastructure or for over-track structures, nor the extra costs of building over the

220 Conclusions and recommendations

railway infrastructure. More in-depth study on these costs could give a clearer picture of the feasibility of these projects. • A number of interviews have established the outline of the project organisation for the reference projects. Further research is recommended on project organisation and on the commitment of the different parties involved. This could yield further insight into the factors that make it possible to bring parties together in successful projects to develop property over railway infrastructure.

Design requirements • A quality assessment and general framework of design demands have been indicated for transport quality, specifically for the platform area. This is only a first step, and further research could lead to a more specific schedule of requirements. • Vibration remains a complicated issue in the design of over-track buildings. Some research is available and was interpreted for this research, but detailed modelling of vibration and its effect on overhead buildings is recommended. Two specific issues are interesting in this respect. Firstly, a large number of different trains use the track, generating different types of vibration, all of which can affect overhead buildings. This is a fundamental difference by comparison with buildings over metro lines, which only need to be isolated against one frequency. Secondly, it is possible so to modify the structural design as to make expensive mass-spring systems unnecessary. More research on the possibilities and costs of these measures could reduce the extra costs related to vibration. • One result of the research on physical safety was the HR-3D method. This three-dimensional differentiated risk analysis approach is still at the conceptual stage and requires quantitative follow-up. Measures that are not yet included in available risk models need to be further developed in order to integrate them into generally accepted risk models. This aspect is missing from currently available risk models and that is unjustifiably impeding property development, not only over and near railways but also over and near infrastructure in general.

Structural design • Another subject that has not been treated in depth, but will become an interesting field of research as more projects involving multiple and intensive use are carried out, is the method of construction and, linked to that, the arrangement and operation of the construction site. In a dense environment, construction – and especially the construction site – constitute major cost elements that could be optimised with more knowledge on how to arrange them. • Railway logistics could also be researched in more depth, as could the question of how railway logistics can be so modified as to facilitate construction over the track. Currently, construction work must be carried out at night, in a limited number of hours. Weekend possessions (with more hours) are sometimes available, but building at night or weekends remains a cost factor.

Financial appraisal • Given the significant difference in costs between locations, it would be useful to study railway locations other than inner-city environments. A necessary step in developing such projects and in acquiring experience in setting them up is to identify locations with both a lower

221 Rail Estate

degree of technical complexity than the inner-city locations currently studied and a minimal difference in rent level. With substantially lower investment costs, and despite somewhat lower direct returns, these locations might be more feasible, at a lower risk level, than complex projects such as the IBIS Hotel over the tracks at Amsterdam Centraal. • This research on structural design and feasibility mainly focused on office development over railway infrastructure. Additional research could focus on the development of apartment buildings and on specific types of resident for them. Station areas in a suburban environment could be an interesting location for couples whose children have left home, young urban professionals or couples with two incomes and no children. The availability of a rail link and (in many cases) good car access could provide an interesting base for groups of users that do not want to live in a real suburban environment but prefer urban areas with many cultural and leisure facilities. Retail and leisure could also be researched in more detail. Many people pass the station area every day, providing a large potential customer base for such functions. • The research on the financial benefits of building over the track constitutes the first steps in determining relevant parameters. Additional research could be done on the possibility of using the value of air rights to make over-track buildings feasible. Such research should also include a closer study of the indirect financial benefits of these projects and the tax measures that could be used to stimulate them. • This research looked very briefly at value engineering for over-track buildings. More variants could be studied, and these could include more real-life locations. That would give greater insight into the frequency with which the extra cost elements actually arise and into measures to control them. Clearly, unexpected extra costs are a significant threat to the successful execution of these projects.

Risk analysis on both the technical and the financial aspects of building over track can also be recommended as additional research. A clear risk analysis that serves all stakeholders in the development of these projects could be an important contribution to stimulating and conducting more projects involving multiple and intensive use of space. The public-private partnerships required to set up a balanced business case are leading to increasingly complex stakeholder structures. As a result, an objective and impartial risk analysis will become a condition sine qua non. Such risk analyses are not yet available and could become a key variable in all stages of such projects.

In addition to the areas of research outlined above, it would be advisable to conduct research on government policy regarding multiple and intensive use of space in station areas. Many project studies have been carried out and many individual projects have been subsidised because they boosted local urban quality. Research could be conducted on new financial (tax) instruments that would stimulate these projects in an autonomous fashion, so that local initiatives do not depend on a project-based subsidy financed by central government. This would give projects involving multiple and intensive use of space more autonomy and possibly a less complex stakeholder process. In turn, this would stimulate entrepreneurial initiatives, leading to more of what one could term ‘rail estate’ – projects involving multiple and intensive use of space in station areas.

222 Introduction

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Rabenek, A., Broadgate and the beaux arts, Architects’ Journal, 24 October 1990, pp. 36-51. Railinfrabeheer, OntwerpVoorschriften voor de Spoorwegbouw, Ontwerpvoorschrift voor kunstwerken, Deel 2 kunstwerken over en naast het spoor, Railinfrabeheer, October 2001, 31 pp. Railned, Basisstation, Functionele normen en richtlijnen voor stations / OV-knopen, Railned, Utrecht, 1999. Reina, P., Trade contractors, Building, 22 July 1988, pp. 32-33. Ridout, G., Arch revival, Building, 17 March 1989, pp. 39-44. RIVM, Nuchter omgaan met risico’s, RIVM, Bilthoven, 2003, 52 pp. Rivolta, A., King’s Cross Termina, l’Arca, No. 41, 1990, pp. 40-47. Rodenburg, C.A., Measuring Benefits of Multifunctional Land Use, Stated Preference Studies on the Amsterdam Zuidas, PhD thesis, Free University Amsterdam, 2005, 208 pp. Rogers, L., A hard stare at Paddington, Archtitects’ Journal, 4 April 1990, pp. 26-31. Rosehaugh Stanhope Developments plc., Broadgate, Penhurst Press, England, 1988, 68 pp. Ross, J., Railway Stations: planning, design and management, Architectural Press, Oxford, 2000.

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Schlichting, K.C., Grand Central Terminal: railroads, engineering, and architecture in New York City, The John Hopkins University Press, Baltimore, 2001, 243 pp. SEMAPA, Paris Rive Gauche, Ville de Paris, SEMAPA, 199?, 28 pp. Shanghai Urban Planning and Design Research Institute, Summary of the comprehensive plan of Shanghai (1990-2020), Shanghai, 2003, 60 pp. Soede, W. (ed.), Hinderlijkheid van contactgeluid met laagfrequent karakter veroorzaakt door trillingen vanwege ondergrondse infrastructuur, Fase 1: Praktijk/literatuurstudie, Centrum voor Ondergronds Bouwen, Gouda, 2001, 21 pp. Spaans, M., Realisatie van stedelijke revitaliseringsprojecten, een internationale vergelijking, Delft University Press, Delft, 2000, 377 pp. Spits, LPG geladen tankauto op A2 in brand gevlogen, 15 July 2003. Spring, M., Stretching City limits, Building, 14 October 1988, pp. 41-48. Spring, M., Triumphal Arch, Building, 25 January 1991, pp. 45-50. Staalduinen, P.C. van & Vecht, J. van der, Hinder voor personen in gebouwen, Meet- en beoordelingsrichtlijn, SBR Richtlijn Deel B, SBR, Rotterdam, 2002, 35 pp. Staalprijzen, www.staalprijzen.nl, September 2005. Staatsblad, Spoorwegwet, Staatsblad No. 264, 2003, 40 pp. Stadtentwicklung Berlin, Planungen für die Hauptstadt, 10 Jahre Hauptstadtbeschluss, November 2001. Starossek, U., & Wolff, M., Progressive Collapse: Design Strategies, IABSE Symposium Metropolitan Habitats and Infrastructure, Lisbon, September 2004, 8 pp. Stoter, J.E. & Ploeger, H.D., Property in 3D – registration of multiple use of space: current practise in Holland and the need for a 3D cadastre, Computers, Environment and Urban Systems, Pergamon, 2003, 18 pp. Studieconsortium Rail-Locatie-Ontwikkeling, Raillocaties referentie projecten, Nieuwegein, 2001, 24 pp. Suddle, S, Physical Safety in Multiple Use of Space, PhD thesis, TU Delft, Delft, 2004, 161 pp. Suddle, S.I., Veiligheid van bouwen bij Meervoudig Ruimtegebruik, thesis, TU Delft, 2001, 298 pp. Suddle, S.I., Wilde, Th.S. de & Ale, B.J.M., The 3rd dimension of risk contours in multiple use of space, ESReDA 23rd seminar, Decision analysis: Methodology and application for safety of transportation and process industries, 2002, 12 pp. Südmeier, I., Het gelaagde landschap, Meervoudig ruimtegebruik in perspectief, EMR i.o., Gouda, 1999, 88 pp.

Tilman, H., King’s Cross Londen, Masterplan van Norman Foster, de Architect, themanummer 44, 1991, pp. 48-51. Tiry, C., Tokyo Yamanote Line – Cityscape Mutations, Japan Railway & Transport Review, September 1997, pp. 4-11. Toneman, L.H.J., et al., Het verschijnsel ‘BLEVE’, Ministerie van Binnenlandse Zaken, 1978, 48 pp.

230 References

V&W, Bijlagen bij Inventarisatie van EV-risico’s bij het vervoer van gevaarlijke stoffen, Ministerie van Verkeer en Waterstaat, 2006, 62 pp. V&W, Nota Mobiliteit, The Hague, 2004, 160 pp. V&W, Nota Risico-normering vervoer gevaarlijke stoffen, 1996, 22 pp. Vákár, L.I. & Snijder, H.H., Railway station structures designed for densely populated urban areas, Structural Engineering International, Volume 11, No. 2, 2001, pp. 128-138. Vákár, L.I., Station Rotterdam Blaak, Overkapping vormt aureool boven hoofd van reiziger, Bouwen met Staal, No. 5, 1993, pp. 27-35. Vambersky, J.N.J.A., Wilde, Th.S. de, & Suddle, S.I., Derde dimensie zorgt voor hiaten in regelgeving, Land + Water, No. 10, 2002, pp. 32-35. VBI, VBI Systeemvloeren, VBI, Huissen, 1998, 32 pp. Vecht, H. van der, Geluids- en trillingsreducerende maatregelen aan Souterrain Tramtunnel Den Haag optimaal afgestemd op de situatie, Geluid, No. 4, 2003, pp. 133-137. Verbart, J., Management van ruimtelijke kwaliteit, De ontwikkeling en verankering van inrichtingsconcepten in het Utrechtse stationsgebied, Eburon, Delft, 2004, 286 pp. Vivico, Information provided by developer Vivico on Lehrter Stadtquartier, Vivico Real Estate, 2002, 8 pp. Vliet, M. van, & Kreukels, T., Verruimd Perspectief, Een internationale verkenning naar ruimtelijke inrichting en meervoudig ruimtegebruik, Habiforum, Gouda, 2001, 101 pp. VNG, Handreiking externe veiligheid vervoer gevaarlijke stoffen, VNG Uitgeverij, The Hague, 1998, 112 pp. Vreeker, R., Urban Multifunctional Land Use and Externalities, ERSA, 2004, 18 pp. VROM & V&W, Verantwoorde risico’s, veilige ruimte, The Hague, 2003, 164 pp. VROM, LNV, V en W en EZ, Nota Ruimte, The Hague, 2004. VROM, Ruimte maken, Ruimte delen: Vijfde Nota over de ruimtelijke ordening 2000/2020, Ministerie van VROM, Den Haag, 2000, 300 pp.

Wagenaar, M., Stedebouw en burgerlijke vrijheid, De contrasterende carrières van zes Europese hoofdsteden, Uitgeverij Thoth, Bussum, 1998, 279 pp. Wijk, M., & Luten, I., Tussen mens en plek, over de ergonomie van de fysieke omgeving, Delft University Press Blue Print, Delft, 2001, 151 pp. Wilde, S. de, & Dobbelsteen, A. van den, Space use optimisation, An international comparison of cases, Journal of Environmental Management, No. 73, 2004, pp. 91-101. Wilde, Th.S. de, Ropers, S.D. & Snel, H.H., Veiligheid en ruimtelijk ontwerp [report for Ministry of Spatial Planning], Holland Railconsult, 2003, 13 pp. Wilde, Th.S. de, Externe Veiligheid Piazza Eindhoven, Maatregelen spoorinfrastructuur, Holland Railconsult, Utrecht, 2004, 19 pp. Wilde, Th.S., et al, Vastgoed naast en boven sporen, Onderzoek veiligheidsaspecten [not available to the public], Holland Railconsult, 2003, 81 pp. Witsen, M. van, Het doodknuffelen van het railvervoer, Verkeerskunde, nr. 5, 2002, pp. 54-55.

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232 Introduction

Appendix A Structural calculations

This appendix will discuss the configuration of the computer model used to calculate the over-track bearing structures. The model makes it possible to calculate the costs of these bearing structures and to compare them with those of a standard bearing structure.

A.1 Configuration of the calculation model

The input consists of the primary spans, the loads, the structural design principles and wind effects. Because the longest primary span will be approximately 30 m, only the track-derived and transfer structures were modelled, not the mega transfer structure. The software used for the calculations was Technosoft Raamwerken (frameworks), Technosoft Liggers (beams) and Technosoft Kolomwapening (column reinforcement).

A.1.1 Primary spans The track-derived structure and the transfer structure were compared for spans of between 10 m and 30 m. The primary span lies perpendicular to the track, as a primary span longitudinal to the track is only possible if the floor perpendicular to the track does not exceed 15 m. To comply with standard office measurements, the spans were based on grids of n x 5.40 m and n x 7.20 m. The table below gives the six spans used in the model. In all cases, the secondary span was 7.20 m, using standard hollow-core slab floors.

Railway spans < 1.80 m grid 10.80 12.60 14.40 16.20 18.00 19.80 21.60 23.40 25.20 27.00 28.80 for the computer model, based on 5.40 m and 7.20 m Possible standard grids railway spans [m]

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A.1.2 Primary spans on the basis of building grid combinations In addition to the spans calculated, combining the 5.40 m and 7.20 grids would make it possible to obtain other span lengths. Such combinations allow any grid to be built up, in multiples of 1.80 m. These other grids are shown in the table below. Using a 6.00 m grid would offer further possibilities. The alternative grid combinations have not been calculated here, but the costs would be comparable.

< Railway spans based on combinations of 5.40 m and 7.20 m grids

7.2 5.4 7.2 5.4 5.4 7.2 5.4

< Scheme for a transfer structure 3.6 with a combination 7.2 of 5.40 m and 3.6 7.20 m building grids 3.6 7.2 3.6 7.2

19.8 23.4

A.1.3 Loads The loads on the overhead building can be divided into dead loads, variable loads and wind loads. The floors will be hollow concrete slabs with a finishing layer, and light partition walls are assumed. To calculate the various structures, the linear load on the beams is based on a secondary floor span of 7.20 m. The loads are applied to the structure in combination. The bearing points of the lowest floor have an extra horizontal support for stability. This stability is attained independently of the building structure. • The total dead load is 4.80 kN/m2, which is a combination of 3.00 kN/m2 for the hollow core slab, 1.00 kN/m2 for the cement screed and 0.80 kN/m2 for light partitioning walls. This gives a toal linear load on the beams of 35 kN/m.

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• The variable load on the floor is 2.50 kN/m2 according to the Nederlands Normalisatie Instituut (NNI, the Dutch institute for standardisation) [NNI, 1990]. This gives a linear load of 18 kN/m on the beams. • The wind load is divided into wind pressure and wind suction and is 1.20 kN/m2 in total, which equates to a vertical load of 9 kN/m applied to the bearing structure [NNI, 1990].

According to NNI [NNI, 1990] the Serviceability Limit State can be calculated by summing the above loads and applying a load factor of 1.0. For the variable load, a factor for instanta- neous loading of 0.5 is used (0.5 x 18 kN/m = 9 kN/m).

Dead load, < variable load and wind loads

Combination < of loads on the overhead building: dead load, variable load and wind load

A.1.4 Strength and stiffness requirements The structures are verified for strength and stiffness. Strength requirements are applied for both steel and concrete, as both will be used: 2 • Steel: Fe 510 (fy = 355 N/mm ) 2 • Concrete: B45 (f’b = 27 N/mm )

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There are stiffness requirements regarding both the vertical deformation of the beams and the horizontal deformation of the building:

• Vertical: the vertical bending of the beams is set at 0.003 times their length, under the influence of the variable load only. Bending due to dead loads is compensated for by a camber in the beams. • Horizontal: the horizontal deformation of a building must be limited to 0.002 times its height [NNI, 1990]. For the calculation, the rotation of the foundation is estimated to account for 50% of this horizontal deformation. The horizontal stiffness requirement is therefore that the horizontal deformation of the building structure not exceed 0.001 times the height of the building.

A.1.5 Track-derived structure A track-derived structure can be arranged perpendicular or longitudinal to the track.

• For the perpendicular case, all spans have been calculated, for a four-floor and for a ten-floor building. The spans used are four times 10.80 m, three times 14.40 m, three times 16.20 m, two times 21.60 m, two times 27.00 m and two times 28.80 m. The beam sections were determined by modelling a beam on two bearing points. The column sections were determined from forces calculated in the model. • Longitudinal to the track, only a 14.40 span is possible, due to the depth of the office building.

A.1.6 Transfer structure A transfer structure can also be arranged perpendicular or longitudinal to the track. Trans- fer structures offer more span options in the longitudinal orientation than do track-derived structures.

• For the perpendicular case, all combinations of primary spans presented in A.1.1 were calculated, for both the 5.40 m grid and the 7.20 m grid. • Longitudinal to the track, spans of 21.60 m and 28.80 m are also possible, in addition to the 14.40 m span. The transfer structure will be wider than the office building it carries, which still has an office depth of 14.40 m. Variations with a 5.40 m grid longitudinal to the track have been omitted, because the width of the office is only 14.40 m, which is two grids of 7.20 m.

A.1.7 Stability and wind effects The wind loads generate horizontal bending, which can be reduced by wind bracing. The most unfavourable situation for wind load is a 14.40 m grid longitudinal to the track. This situation has been modelled with and without wind bracing to see whether wind bracing would reduce horizontal bending sufficiently. Without bracing, the structure has a horizontal deformation of 54 mm, which exceeds the maximum deformation of 1/1 000 of 43 m, i.e. 43 mm. Fur- thermore, the structure without wind bracing would have to take up bending moments in the joints, which would increase construction costs. Introducing wind bracing reduces horizontal

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bending to 16.4 mm, which is well within the margin of 43 mm. For the calculations on the other structures, wind bracing will also limit the horizontal bending of the framework above the transfer structure to within permissible limits, as the example calculated represents the most unfavourable situation. Likewise, in the case of a track-derived structure longitudinal to the track, wind bracing will so take up the horizontal loads as to limit horizontal bending to

less than 0.001 times the height of the building. < 54 54 A 14.40 m grid -54

-16.5 -16.4 -16.4 transfer structure -2.26 longitudinal to the 2.21 track, without wind

43.8 -12.8 bracing 2.16 -12.8 2.99 -12.8 2.09 -2.17 2.66

8.9 8.9 < < < 1.98 2.32

A 14.40 m grid 21.5

21.5 transfer structure 1.83 1.98

-4.89 longitudinal to the -3.14 -4.88 track, with wind bracing -1.26

1.39 1.39

-2.77 -2.77

A.2 Costs of primary bearing structures

This section will compare the cost per square metre of gross floor area for the structures calculated. The variants calculated are: track-derived structure, transfer structure, all different span lengths, span perpendicular, span longitudinal, four floors and ten floors.

A.2.1 Costs of the structural elements To determine the cost of the primary bearing structure, it is necessary first to establish the prices for individual elements. These are then used in the calculations below. Prices are taken from Elsevier Building Costs, staalprijzen.nl (steel prices) and bouwkosten-online.nl (building costs online), and have been cross-checked.

Steel: For steel elements (HEx profiles), the basic price is € 1/kg. This basic price is dou- bled for standard elements for assembly and placement, so we shall take € 2/kg. For the transfer structure, € 3/kg is used, as the structure involves more work and placing the structure directly above the track is more complex. For the steel structures of the reference building and the transfer structure, an additional € 5 is added per square metre of gross floor area for fire-resistant coating.

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Concrete: Concrete elements do not have a standard price per cubic metre. Their price depends on the form and dimensions of the section. To determine the price of the various concrete elements, the prices of standard columns and beams have been interpolated. Small elements have a relatively high price per cubic metre, whereas larger elements are cheaper per cubic metre. The references for the beams are taken from the civil engineering structures in Elsevier Building Costs. Columns of these sizes for an office building will be less expensive, as the dynamic loads are lower in magnitude and fewer in number. The costs per m3 are therefore reduced to 80% of the beam costs.

Cost of concrete elements

2500 Column < Costs of concrete Beam columns and 2000 1920 beams

1600 1500 1380 3

1150 1140 € /m 1000 950 960 840 800 750 660 700 625 550 500

0 400 500 600 700 800 900 1000 1200 Width (mm)

Costs of concrete columns and beams

Floors: The floor elements are hollow-core slabs. Hollow-core slabs of 7.20 m cost € 50/m2.

A.2.2 Standard office structure The track-derived structure and the transfer structure will be compared to a standard bearing structure, to determine the extra cost of the primary bearing structure for a building over railway infrastructure. The steel framework that will be used for the reference building is similar to the structure that will be used for the overhead building on the transfer structure. The result is represented in the table below. Both the columns and the beams consist of HE320A sections. The steel structure itself costs € 66/m2. To determine the cost of the primary bearing structure, € 50/m2 must be added for the hollow-core slabs and € 5/m2 for the fire-resistant coating of the steel structure. On this basis, the primary bearing structure of a standard office costs € 121/m2, which tallies with other sources of building cost estimates [Evers, 2003]. A similar calculation was performed for a steel framework with a grid of 5.40 m. With a 5.40 m grid, HE280A steel sections are used. The cost of

238 Structural calculations

the framework was estimated at € 73/m2, giving a cost of € 128/m2 for the primary bearing structure, including hollow-core slabs and fire-resistant coating. The cost of a standard

bearing structure is set at € 120/m2. Example of cost < calculation for a reference building with a 7.20 m grid

A.2.3 Track-derived structures For the track-derived structure, all beams have an equal span and size. A structure perpendicular to the track has three bays, which are assumed to consist of the same elements. The sections of the columns for the office building will differ between floors, as the load imposed on them will differ. An average size is taken for cost calculation purposes. The lower columns (the columns under the building) have been calculated separately. The table below gives one example of this cost calculation, for a track-derived structure perpendicular to the track, with a primary span of 14.40 m and four floors. The total cost of the beams and columns is € 154/m2. Including the cost of the hollow-core slabs (€ 50/m2), the primary bearing

structure costs € 204/m2. Example of cost < calculation for a track-derived structure of 14.40 m perpendicular to the track

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The table below shows the results for all the track-derived structures calculated. As the length of the span increases, the extra cost of the structure rises substantially. It is virtually impossible to use spans of 27.00 m and 28.80 m in practice, mainly due to construction problems. A span of 21.60 m is possible, but expensive.

Primary span < Costs of overhead buildings with 2 2 track-derived structures for 2 2 2 2 different spans, 2 2 grids and numbers of floors

2 2 2 2 2 2

A.2.4 Transfer structures A similar analysis was carried out for the transfer structure. The structures of all different spans were calculated and the costs of the resulting profiles derived. For this calculation, HE sections were used, as they are relatively easy to use and relatively cheap compared to hollow steel sections. The table below contains one example of a cost estimate, for a transfer structure with a span of 21.60 m perpendicular to the track and four floors. The cost of the steel structure is € 145/m2. € 50/m2 must be added for hollow-core slab floors, plus € 5/m2 for fire-resistant coating, bringing the cost of the primary bearing structure to € 200/m2.

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Structural calculations Example cost < calculation for a transfer structure of 21.60 m perpendicular to the track

The table below shows the results of all the cost calculations for the transfer structure.

Costs of overhead < Four floors Ten floors buildings with a Perpendicular Longitudinal Perpendicular Longitudinal transfer structure for different spans, grids and number of floors

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242 Introduction

Appendix B Cost analyses

This appendix will compare the cost of property development over the track with that of standard property development. An amount of € 1 200/m2 has been set as a reference for the construction cost of a normal inner-city office building. This € 1 200 will be the reference for all other cost components within this study and the extra cost of building over the track will be related to this € 1 200/m2 in percentages. The extra cost is indicated per square metre of gross office floor area for the four-floor building (2 488 m2) and the ten-floor building (6 221 m2) modelled in Chapter 8.

The structure of the cost analysis has been discussed with Robert Cijs of NS Vastgoed, who is a cost engineer involved in many property development projects over and near railway infrastructure. He also provided data for setting up the cost analysis, partly based on the extension of the IBIS Hotel over the tracks at Amsterdam Centraal, which is a very relevant reference for many of the cost elements. The result of the analysis has subsequently been checked by Ruud Weterman of Movares, another cost engineer involved in many property development projects over and near railways.

B.1 Extra construction costs

The extra construction costs for an over-track building are divided into three parts: • Costs of changes in the railway infrastructure that are necessary for overhead construction. • Costs that result from the structural design of the building and the choice of a track-derived or transfer structure. • Costs that result from building over railway tracks in general.

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We shall discuss these three categories of extra construction cost in the following sections. All elements will be related to the € 1 200/m2 in percentages, and the difference between these costs and those for normal construction are related to the elements of the reference standard inner-city office building (hereafter referred to as the reference building).

< Costs for the standard inner-city office building as a reference [Based on information provided by Robert Cijs of NS Vastgoed]

B.1.1 Measures related to railway infrastructure There may be a need for various measures related to railway infrastructure. It may be necessary to modify the overhead line and, in more complex situations, it might also be necessary to modify track and railway systems. There may also be costs for safety measures.

Modifications to the overhead line The cost estimate for modifying the overhead line has been derived from the costs for this item on the IBIS Hotel project. Modifying the overhead on four tracks cost € 500 000. A building perpendicular to the tracks has about four tracks running under it. If the overhead line needs to be adjusted for the four-floor building it will cost € 200/m2 (€ 500 000 / 2 488 m2) and for a ten-floor building it will cost € 80/m2 (€ 500 000 / 6 221 m2). This is an increase of 16.7% and 6.6% respectively over the standard construction cost of € 1 200/m2.

Modifications to track and railway systems If it is necessary to modify the track or railway systems, the cost will be even higher. Modify- ing four tracks will cost € 6 800 per running metre. However, any adjustments will extend over a length well in excess of that for which the building covers the track. It has been

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estimated that track will need to be modified over 200 m, which will cost € 1 360 000. For a four-floor building this is an increase of € 546/m2 or 45.5% and for a ten-floor building an increase of € 218/m2 or 18.1%.

Railway safety measures Ensuring physical safety will require infrastructure measures. Many measures are possible, but two are particularly effective. One is to construct a derailment guide beside the tracks to guide a train if it derails. This may cost about € 100 000. Another measure, which is very effective for minimising the risks involved in transporting flammable liquids, is a liquid drainage system to prevent pool fires. A liquid drainage system is estimated at € 250 000. Taking both measures adds € 140/m2 to the cost of a four-floor building and € 56/m2 to that of a ten-floor building (11.7% and 4.6% respectively).

When extra costs are incurred for all elements, they may add up to as much as 74% for a four-floor building or 29% for a ten-floor building. However, there may well be no extra costs related to railway infrastructure, for instance where the infrastructure has already been designed for an overhead building.

B.1.2 Track-derived structure The cost components of a structure differ according to the design. We shall look at the track-derived structure and the transfer structure separately. This subsection discusses the extra costs for a track-derived structure, comparing to the construction cost of € 1 200/m2 for the reference building.

Foundations The foundations of a standard inner-city office building generally account for 5% of the construction cost. Chapter 8 looked at three different foundation alternatives. The first is a foundation on a tunnel. If a tunnel is designed to be built over, there will be no foundation costs for the overhead building. This is a saving of 5% of the construction cost. For a foundation at ground level, a normal pile foundation is not possible. The large spans mean that foundations will be concentrated into strips, while the larger loadings may render normal piles inadequate. When bored piles are needed the foundation way be twice as expensive, leading to 5% extra cost. When the tracks lie at Level +1, the foundations may be even more complex. As a maximum, it is estimated that the foundations could be three times as expensive as a normal pile foundation, in which case the extra cost would be 10%.

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Track-derived structure The extra cost of the primary bearing structure was determined in Chapter 8 for track-derived structures with various span lengths. The result for the four-floor building was a 48% – 159% increase in the cost of the primary bearing structure. As the primary bearing structure accounts for 10% of the construction cost, the extra cost for a track-derived structure of four floors over railway tracks is 4.8% – 15.9%. The extra cost of a track-derived structure for a ten-floor building over railway tracks is 41% – 136%. The extra cost for a ten-floor over-track structure is therefore 4.1% – 13.6%.

Cores The cores account for 5% of the cost of a standard office building. The cores of an over-track building are the same. The only potential extra cost is that of extending these cores to ground level. For both a four-floor and a ten-floor building, the extra length will be about 7 m, which corresponds to two floors. If the cores need to be extended to ground level, the extra cost for them is 50% for a four-floor building (two floors added to four) or 20% for a ten-floor building (two floors added to ten). The possible extra cost for cores compared to the construction cost is 2.5% for a four-floor building (50% of 5%) and 1% for a ten-floor building (20% of 5%).

Façade The façade of a track-derived structure will be more expensive, because the height between floors is greater than for a standard office building. The extra height for a 14.40 m span is about 20 cm (3.80 m in total), which is 5% extra façade surface compared to the 3.60 m of a standard building. This rises to about 60 cm for a 28.80 m span, which is 15% of 3.60 m. The extra cost of the façade compared to the total construction cost is 1.4% – 4% (5% – 15% of 27%). This applies to both the four-floor and the ten-floor buildings.

Building services Building services will also cost more. Here, two components determine the extra cost. Extra specifications might be necessary and there will be extra costs for the extra volume of the building with a track-derived structure, as for the extra cost of the façade. The extra costs for building services arise from the location over the railway tracks. It might be necessary to put the building services on the roof for electromagnetic compatibility or because arrangements are needed to connect water, electricity and sewerage systems. The extra cost is estimated at between 0% and 5% of the building services cost, which equates to 0% – 1.5% of the construction cost. The extra cost resulting from the extra volume of the track-derived structure is 1.5% – 4.5% of the construction cost (5% – 15% of 30%).

Construction site There is no standard figure for construction site costs. Even more than the location over the railway, the direct surroundings determine the options for constructing a building and organising a construction site. It is estimated that a construction site near railway tracks will always be more expensive than a normal site. The site for the IBIS Hotel extension

246 Cost analyses

above the tracks at Amsterdam Centraal is three times as expensive as a normal site. For the purposes of this study, it is estimated that an over-track construction site will be 25% – 200% more expensive than a normal site. This will add 2% – 16% to the cost of construction (25% – 200% of 8%).

By comparison with a standard building of the same height, a track-derived structure increases construction cost by between 4.7% and 54.5% for a four-floor building and 4.0% – 50.7% for a ten-floor building.

B.1.3 Transfer structure The cost components of a structure differ according to the design. We shall look at the track-derived structure and the transfer structure separately. This subsection discusses the extra costs for a transfer structure, comparing them to the construction cost of € 1 200/m2 for the reference building. Where a cost element is the same as that for the track-derived structure, the text will refer to the previous subsection.

Foundations As for the track-derived structure.

Transfer structure The extra cost of the primary bearing structure was determined in Chapter 8 for transfer structures with various span lengths. The result for the four-floor building was a 38% – 97% increase in the cost of the primary bearing structure. As the primary bearing structure accounts for 10% of the construction cost, the extra cost for the primary bearing structure of four floors over railway tracks is 3.9% – 9.7%. The extra cost of the primary bearing structure for a ten-floor building over railway tracks is 19% - 67%. The extra cost for a ten-floor over-track structure is therefore 1.9% – 6.7%.

Cores As for the track-derived structure.

Façade As the floor height is the same as that of a standard office building, there is no extra cost for the façade of a transfer structure.

247 Rail Estate

Building services Of the extra costs mentioned in connection with the track-derived structure, only the extra costs because of the location over the tracks will be incurred. The extra cost is estimated at between 0% and 5% of the building services cost, which equates to 0% – 1.5% of the construction cost.

Construction site As for the track-derived structure.

By comparison with a standard building of the same height, a transfer structure increases construction cost by between 0.8% and 39.7% for a four-floor building. The difference for a ten-floor building lies between -1.0% and 35.2%

B.1.4 Measures associated with building over railways in general Some cost components do not depend on the type of structure. These are the measures linked to vibration, noise, electromagnetic compatibility, safety, finishing the underside of the building and maintenance, plus the connection to ground level.

Vibration measures Trains, especially freight trains, cause vibration in the ground that can enter the over-track building and cause disturbance to users. As discussed in Chapter 6, measures should preferably be taken in the structural design. If that is not possible, rubber mats or springs can be used. If the vibration problem can be solved in the structure, there is no extra cost for vibration measures. Springs are the most expensive option, and can carry a standard vertical load. In the case of the Orient Express building above Rijswijk Station, about € 300 000 was invested in 1 125 springs (€ 250 000 in 1996) [Hoekveld, 2004]. Each spring carries 67 kN of vertical load. This means that these springs cost € 4/kN (€ 300 000 / (1 125 x 67)). A building weighs about 10 kN/m2, so springs cost about € 40/m2. As a reference, for the IBIS Hotel extension € 165 000 has been invested in 5 000 m2 of hotel space above the tracks. These springs cost € 33/m2. An amount of € 35/m2 is assumed for the extra cost of springs in an overhead building, which corresponds to 3.0% of the standard construction cost.

248 Cost analyses

Noise measures Special noise reduction measures are an extra cost item. Such costs are only counted if they are for measures that are not needed in buildings beside the track. The only aspect that might raise the cost of the façade is that overhead buildings perpendicular to the tracks may have two exterior walls exposed to train noise. The most common measure affecting the façade is the use of thicker windows. The maximum extra cost is estimated at 10% extra for half the façade. Compared to the construction cost, this equates to a maximum of 1.4% (50% of 10% of 27%).

Electromagnetic compatibility measures Electromagnetic compatibility is a field that is still undergoing research. Measures include changing the way building services are laid, out screening some of the electromagnetic radiation. These measures cannot be calculated, so 1% of the construction cost is arbitrarily taken as a maximum for the four-floor building. The measures for the ten-floor building are the same, divided over a larger number of square metre, giving 0.4%.

Building safety measures A broad range of safety measures is possible. The choice of measures will depend on the local situation and will be made in cooperation with specialists from the fire brigade. One basic measure is adding a secondary exit, which is already combined with the extra cost for the cores. What is always needed is a covering layer for the underside of the building. This is part of the finishing of the underside of the building, which is dealt with below. Arbitrarily, 2.0% is taken as a maximum for other measures.

Finishing of underside In some cases, the building will be over the platform area. In such cases, the underside of the building must be finished to a higher standard. This can cost up to € 30/m2. The finishing will be required over an area of 14.40 m x 43.20 m, which will cost € 19 000. For the four-floor building, the extra cost is 0.6% of the construction cost. For a ten-floor building it will be 0.2%.

Maintenance measures An office building over railway infrastructure can incorporate basic measures to facilitate maintenance. One extra measure that needs to be taken is an extended floor around the building. This floor can be constructed in such a way that it serves as a crash deck during construction. A basic floor around the building can be about 3 m wide and can be built for € 300/m2. Such a floor will cost € 100 000 (3 x (14.4 + 14.4 + 43.2 + 43.2) m2 x € 300/m2). For the four-floor building, this will add € 40/m2 by comparison with the standard construction cost of € 1 200/m2 (3.3%). For the ten-floor building this amount corresponds to 1.3% of the construction cost.

Connection to ground level A building over railway infrastructure must have an entrance connected to ground level. Chapter 8 presented various solutions, of which a special entrance to ground level just for that specific building is the most expensive. A connection to ground level is made by

249 Rail Estate

a combination of a staircase and a lift. A staircase and lift each cost € 150 000. Com- bined with the cost of the contractor (20%) the total construction cost for the two is € 360 000. For the four-floor building, this is € 145/m2 or 12% of the construction cost. For the ten-floor building this is € 58/m2 or 4.8%. Both amounts are maximum values. When a building is directly connected to a building at ground level, there are no extra costs.

The extra construction cost for general measures because of building over railways is 23.3% compared to a standard building of four floors and 13.1% for ten floors.

Extra construction costs, general measures

B.2 Extra additional costs

The additional costs will also differ from those for the reference building. The extra direct additional costs and the extra indirect additional costs will be discussed below. It is assumed that the additional cost percentage is at least as high as that for the reference building, which means that this category of cost is higher in absolute terms because the construction cost is higher. Certain elements will increase these costs above that minimum.

Extra direct additional costs The extra direct additional costs may be higher for design, management and other consultancy services. The amount in euro will increase, because the cost of consultancy services is related to the construction cost (10% for design and 4% for management). In addition, the complexity of the project might lead to an increase in excess of this standard percentage. The maximum extra cost for consultancy services is estimated at 50% above the normal percentage. This equates to 5.0% of the construction cost for design consultancy (50% of 10%) and 2.0% for management and other consultancy services (50% of 4%).

The other additional costs are also directly related to the higher construction cost, with the maximum increase estimated at 50%.

Extra indirect additional costs The extra indirect costs are estimated in a similar manner to the extra direct additional costs. Risks and contingencies are estimated as being a maximum of 100% higher and financing expenses are estimated at 50% higher, giving extra costs of 4.0% and 2.5% respectively. Line closures and alternative transport also constitute extra costs com-

250 Cost analyses

pared to those for the reference building. These costs are estimated at 10% extra for a four-floor building and 4% for a ten-floor building, based on the assumption that the line is closed for two weeks in total. Higher percentages may very well occur, but it would not be logical to incur higher costs, and other solutions would have to be found.

The extra additional cost for building over the track is 27.5% in the case of four floors and 21.5% for ten floors.

B.3 Overview of total investment cost

The extra cost of building over railway tracks with a track-derived structure and a transfer structure have been combined for a four-floor building and a ten-floor building. An overview of the investment costs appears below.

B.3.1 Cost estimate for a track-derived structure The cost of a building with a track-derived structure and four floors over the tracks is 105% – 270% that of the reference building. The extra cost is therefore 5% – 170%. The cost of a building with a track-derived structure and ten floors over the tracks is 106% – 208% of the reference building. The extra cost is therefore 6% – 108%.

105% 270%

251 Rail Estate

106% 208%

B.3.2 Cost estimate for a transfer structure The cost of a building with a transfer structure and four floors over the tracks is 101% – 256% of the reference building. The extra cost is therefore 1% – 156%. The cost of a building with a transfer structure and ten floors over the tracks is 99% – 192% of the reference building. The cost difference is therefore -1% – 92%.

101% 256%

99% 192%

252 Introduction

Appendix C Interviews

Research for this thesis involved a large number of appointments and interviews. However, two aspects required specific sets of interviews: the reference projects and the financial appraisal. The present Appendix summarises the topics and persons interviewed on these two topics.

C.1 Interviews on reference projects

The table below lists the people interviewed for each reference project. The contact persons on the Zuidas project were not interviewed explicitly; information was gathered during the author’s work on the alternative Multi-storey Dock Model developed by Holland Railconsult (now Movares).

The interviews were not based on a specific set of questions. However, the topics discussed were based on the research criteria in Chapter 4: the origin of the project, the urban context, the application of multiple and intensive use of space, structural solutions chosen and flexibility. The interviewees do not all have the same background, nor did they all play the same role within their respective projects. As a result, the subject focus varied between interviews.

253 Rail Estate

* No specific interviews: detailed information was gathered during author’s participation in engineering work on the Zuidas project.

C.2 Interviews for the financial appraisal

A number of Dutch property development specialists were interviewed to obtain information on the benefits of developing property over railway infrastructure. As there have been few projects of this nature in the Netherlands to date, property development over motorway infrastructure was also included, as there is more experience with that type of project in the Netherlands.

The interviews were held on the basis of an initial analysis of the general benefits of developing property over infrastructure. First, the interviewees were asked about rental income and gross initial yield on property development over railway infrastructure, to compare these with the limited volume of data found. We then discussed a list of potential extra benefits and drawbacks – direct and indirect. A questionnaire sheet was completed for each interview and the results formed the input to Chapter 9.

254 Interviews

Summary

Station locations are of particular interest on account of their being readily accessible, not only by train but also by other forms of public transport. These locations are also sited close to all urban facilities. But the very quality of these locations lies at the root of their problems. Because of their strategic positioning, numerous parties are involved in decision making, and those parties have differing interests. Furthermore, the proximity of rail infrastructure means that a large number of environmental regulations must be complied with. The complexity of the rules is one reason why much space near stations is still undeveloped. Often, this space is occupied by low value industry, and also rail infrastructure occupies a large percentage, in the form of sidings and yards. The present thesis examines the possibilities that exist for building over rail infrastructure. In other words, for developing Rail Estate.

Context

The tendency to build more within towns and cities is leading to projects which, in addition to displaying a high level of urban density, combine a number of different functions – intensive and multiple use of space. Multiple use of space is the combining of different functions, such as living, working, services and infrastructure next to each other (i.e. in two dimensions) or – and that is the focus of the present study – on top of each other (the third dimension). Furthermore, it is possible to achieve multiple use of space over time, be it short-term or

255 Rail Estate

long-term. This is the fourth dimension. It is also possible to combine functions at different levels of scale: within a building, on a site or across an entire area. Intensive use of space is subjective – everyone has a different idea as to what constitutes ‘intensive’. The term refers to the number of square metres developed per hectare of land. This is expressed as a ‘floor space index’. Intensive use of space is also possible in all three spatial dimensions, plus time. Chapter 2 gives real-life examples of all strategies for achieving multiple and intensive use of space. Multiple use of space can lead to higher residual land values through optimum organi- zation of the available space. There are a number of benefits to society, such as conservation of green areas outside towns, reduced pollution and lower transport costs.

Building beside and over tracks in station areas requires an understanding of the specificity of this infrastructure. Comparison of the Netherlands with neighbouring countries reveals that the Netherlands has a comparatively small number of track kilometres per square kilometre, but that those tracks are used more than twice as intensively as are tracks in other countries. This intensive utilization has a major impact on the options for building overhead, as intensive use brings with it more stringent reliability and availability requirements. Chapter 3 defines a number of station types and discusses their effects on the options available for organizing the city around and above them. Stations are categorized according to their functional arrangement (terminus, through or cross station) and the vertical position of their tracks (underground, subsurface, ground level or elevated). Major cities in other countries often have ground level terminus stations (especially in the case of the reference projects), whereas the Netherlands makes extensive use of through stations with elevated tracks (at locations where major projects are planned). Through stations are more difficult to build over than terminus stations, as the tracks are used much more intensively. Elevated tracks are more difficult to build over than are tracks at ground level, because of the greater distance that has to be bridged between true ground level and any artificial ground level over the tracks.

Reference projects

The oldest example is the rebuilding of Grand Central Terminal in New York. At the beginning of the 20th century, an existing ground level station for steam trains was transformed into a two-storey underground station with electrified tracks. ‘Terminal City’ was built overhead, a project that included the famous Waldorf-Astoria Hotel. The busiest station in the world, Shinjuku Station in Tokyo, is being built over, and the new Federation Square cultural centre in Melbourne was built over tracks.

Europe can also boast a number of examples. Chapter 4 analyses six major projects according to a number of criteria, to gain an insight into current practise. In London, Liverpool Street Station has already been built over, and plans are being made to redevelop King’s Cross Railway Lands. In Paris, the Jardin Atlantique has been built over tracks, and the Seine Rive Gauche project will involve building over the tracks of the Gare d’Austerlitz. Lehrter Bahnhof, Berlin’s central station, was completed during 2006, and work should be starting in Amsterdam in the next few years on what will be the largest over-track project: the Zuidas, in which a million square metres will be built over infrastructure.

256 Summary

Analysis of the reference projects allows us to draw some interesting conclusions. In these projects, space alongside the tracks was developed first. The second phase was to make space for new property by optimizing the rail infrastructure. Finally, the space over the track was developed. The projects all have a comparable density, although the smaller projects display a higher density than the larger ones. As regards multiple use of space, the percentages of homes and offices have become more similar over the years, with some 10% to 15% devoted to other functions. There are differences in the proportions of public and private involvement in the development process, in rents and in urban design concepts.

Comparison at an international level also yields points worthy of consideration with regard to practice in the Netherlands. One important difference is that Dutch cities are not built to a high degree of density, which keeps land prices relatively low. This affects the feasibility of complex city-centre building projects. The Netherlands is short of space at a national level, rather than at the level of the individual town or city. One other difference is that – with few exceptions – all Dutch stations are through stations, yielding a higher capacity per track and hence less flexibility for overhead construction. This network of through stations also means that these tracks carry dangerous goods, making external safety an important factor.

Requirements for building over tracks

Quality and flexibility are important requirements with regard to building over railway tracks. Building over platforms takes away daylight, transforming surface platforms into underground platforms. Using examples from the Netherlands and abroad, Chapter 5 discusses the consequences for platforms at various levels relative to ground level. The same chapter also proposes ways of compensating for the negative consequences of platforms’ being underground. These include structural solutions, solutions involving the use of natural and artificial light, and ways of finishing the interior of the station. As well as affecting the quality of the space within the infrastructure, building over tracks affects the quality of the adjacent sector of the town or city. The quality of the urban environment is discussed on the basis of five elements. Flexibility is the ability of a design to continue to meet functional requirements into the future. Flexibility is necessary both for the rail infrastructure and for the elements of the city that lie alongside and above it. This study looks at four types of flexibility: phase-ability, maintainability, changeability and extendibility. The quality and flexibility requirements for both the city and the infrastructure affect each other. Chapter 5 concludes with a discussion of the balance between these requirements.

Quality and flexibility are relatively soft technical requirements. Chapter 6 looks at the hard technical requirements: noise, vibration and electromagnetic compatibility (EMC). The chapter discusses legislation and other types of regulations, the specific problems related to building over tracks, and countermeasures that can be taken at the source, along the transmission path and at the recipient. Study of noise focuses on vertical noise radiation from trains, as the façades of buildings are located above the track. The part of the train above the wheels significantly reduces disturbance due to vertically radiated noise by comparison with that from noise radiated horizontally. Study of vibration looks in particular at the struc-

257 Rail Estate

tural measures that can be taken. In examining EMC, consideration is given to the measures for electrical and magnetic sources that must be taken in order to achieve adequate compatibility, i.e. to eliminate all health hazards and avoid any interference to equipment. Wind nuisance and air quality are also discussed briefly.

While safety is also a technical requirement, the whole of Chapter 7 has been devoted to this aspect in view of the impact of safety on design, especially in terms of the transportation of dangerous goods. What makes safety such a complex factor in relation to over-track construction is that on the one hand the probability of an accident is very low, because rail systems are so safe, whereas on the other hand the potential consequences are very serious. As yet, there have been no major railway accidents in the Netherlands involving dangerous goods. How- ever, a number of near-misses have shown that the risk of such accidents is more than purely hypothetical. As a result, designs must ensure that the probability of an accident is as low as possible, and that adequate precautions have been taken to minimize the consequences of any accident. This study looks mainly at external safety – the risk to persons adjacent to the track of transporting dangerous goods. A distinction is made between individual risk (related to distance from the track) and societal risk (the risk that a group of individuals will die at the same time as the result of an accident). The regulations on individual risk mean that a strip of land alongside the track must be kept clear, and hence can not be developed. Because these regulations are two-dimensional, this means that it is also impossible to develop the space above the track. The regulations concerning societal risk have a lesser specific effect on the area immediately adjacent to the track, but do affect a zone extending out to 200 m from it.

Chapter 7 discusses the HR-3D method. This method is intended to complement existing accepted computer models used to calculate individual and societal risk. HR-3D differenti- ates between types of accident and, for each accident, proposes measures for limiting the consequences. This better reflects the reality of the three-dimensional environment within which construction alongside and above the tracks occurs, of which existing models fail to take sufficient account. To demonstrate the functioning of HR-3D, three projects are discussed, each of them involving a different scale: the Piazza Center (building), Dordrecht (area adjacent to tracks) and the Amsterdam Zuidas (a future urban centre).

Structural design

Building above the track involves stacking a number of different grids. First, there is that of the railway infrastructure. The minimum dimension is determined by the structure gauge, but the space available for structures also depends on the space between the tracks, inspection paths and the presence of platforms, switches and crossings. Chapter 8 defines four locations at which over-track construction is possible: platforms, sidings, parallel tracks and yards. Offices also have standard grids, in multiples of 1.20 m. This yields office sizes of 5.40 m, 6.00 m and 7.20 m. For the present study, the standard office examined in more detail is 43.20 m by 14.40 m. The length of 43.20 m was chosen because this can be made up of either six times 7.20 m or eight times 5.40 m, allowing a number of different span lengths to be used. A width of 14.40 m was selected because this allows for a number of office configurations.

258 Summary

Three types of overhead structure are possible. They differ in the degree to which the building conforms to the spatial constraints of the tracks. The track-derived structure matches the railway infrastructure exactly. Here, the structure is stacked in storeys, possibly with different dimensions for the office. The transfer structure converts the inconvenient grid imposed by the tracks into a standard grid for the offices. This structure provides an intermediate layer on which a standard building can be placed. Finally, there is the mega transfer structure. This crosses the tracks in a single span, and likewise offers the possibility of using a standard office grid. The difference between the mega transfer structure and the transfer structure is that the mega transfer structure occupies more than half the height of the building. The effect of each structure on quality, flexibility, technical aspects and safety is discussed.

Chapter 8 also discusses the factors involved in designing the structure of an over-track building. Naturally, the details of such a design will always depend on local conditions. The length of the primary span is an important design element. It may be possible to orient the building with its primary span parallel to the track axis if it is possible to span the tracks with a single floor. In addition to considering the span length and direction, this chapter looks at ways of ensuring that the track structure is stable and at aspects of the foundations, focusing on the various possible vertical positions of the tracks relative to ground level. The chapter also discusses the choice of materials for the main load bearing structure, together with ways of establishing a functional connection between over-track buildings and ground level. The last topic dealt with under the heading of structural design is the set of conditions related to the construction process. To enable the financial feasibility of over-track construction to be analysed in Chapter 9, Chapter 8 closes with a comparison between the cost of a load-bearing structure over tracks and that of the structure for a standard office. The comparison covers both the track-derived and transfer structures. The variables considered are span length, the orientation of the structure relative to the track and the number of floors.

Financial feasibility

Building above railway tracks is financially feasible if the air rights above the track have a positive value. To determine the value of the air rights, a comparison was made with property alongside the track. In the case of buildings next to the tracks, the investment costs are made up of the cost of the building itself and the cost of the land on which it is built. The land costs are determined on the basis of the residual land value; the potential revenue from a building minus the cost of building it. In the case of buildings over the tracks, the investment costs are made up of the cost of the building itself and the cost of the air rights. The cost of an over-track building is compared with that of a building alongside the track. The additional costs for building over the track are expressed as minimum and maximum percentages of the cost of a standard building next to the track. There is a certain scatter in these values, as the costs depend on the location. For buildings along the track, research was conducted to establish the possible cost of land in comparison with the cost of the building. Comparison between revenue from over-track buildings and that from buildings adjacent to the track revealed that there is no reason to expect higher rental revenue or gross initial return. There are a number of additional points to be taken into consideration regarding buildings over rail-

259 Rail Estate

way lines, but it is reasonable to assume that revenues will be comparable. Using the range of values for the cost of ground next to the tracks and the range of extra costs for building over the track, it is possible to identify a zone within which the air rights have a positive value and in which it is therefore feasible to build over the track.

In conclusion

This thesis focuses on the technical and financial feasibility of building over railway tracks. All technical aspects of over-track construction are covered. Integrated design, together with consideration of all the complex conditions that rail infrastructure imposes, certainly make it possible to build over railway tracks – from a technical point of view. The financial feasibility of so doing is less clear-cut. Residual land values, which form the basis for determining whether the value of the air rights over the track is positive or negative, display a considerable degree of spread. However, this study has shown that the extra costs for over-track construction also vary considerably, depending on location. As a result, the search for locations at which building over railway tracks could be financially feasible will involve more than simply identifying locations at which the price of land is high. The financially ideal location for over-track building is one with minimum technical complexity and maximum land value.

260 Introduction

Samenvatting

Met de vraag naar nieuwe ontwikkellocaties en de wens om de groene ruimte buiten steden vrij te houden is er meer en meer interesse in binnenstedelijke herontwikkeling. Dwars door Europa zien we projecten, waarbij met oog voor de historie van de stad nieuwe en hoogwaardige gebouwen worden ontwikkeld om in te werken en te leven. Binnen deze trend van binnenstedelijk bouwen neemt de stationslocatie een speciale positie in.

Stationslocaties zijn interessante locaties door de goede bereikbaarheid met trein en ander openbaar vervoer dat op deze stations aansluit. Daarnaast zijn deze locaties in de buurt van alle stedelijke voorzieningen. De kwaliteit van deze locaties leidt ook gelijk de problematiek in. Door de strategische ligging zijn vele partijen betrokken en moet rekening worden gehouden met de vele verschillende belangen. De nabijheid van spoorinfrastructuur geeft daarnaast veel eisen vanuit milieuregelgeving. Mede door complexe regelgeving is in stationslocaties veel ruimte nog onontwikkeld. De ruimte is over het algemeen in gebruik door laagwaardige industrie, maar ook de spoorinfrastructuur zelf neemt vele hectaren waardevolle grond in met wisselstraten en spooremplacementen. Dit proefschrift onderzoekt de mogelijkheden om de ruimte boven de spoorinfrastructuur te benutten met vastgoedontwikkeling, ofwel de ontwikkeling van ‘Rail Estate’.

Context

Bij de trend om meer binnenstedelijk te bouwen worden projecten ontwikkeld waarbij naast een hoge stedelijke dichtheid verschillende functies worden gecombineerd; intensief en meervoudig ruimtegebruik. Meervoudig ruimtegebruik gaat over het combineren van verschillende functies, zoals wonen, werken, voorzieningen en infrastructuur in elkaars nabijheid (tweede dimensie), of soms, en specifiek voor deze studie, boven elkaar (derde dimensie). Daarnaast is meervoudig ruimtegebruik ook mogelijk in de tijd, zowel op korte als op lange

261 Rail Estate

termijn (vierde dimensie). Het combineren van verschillende functies is ook mogelijk op verschillende schaalniveaus; binnen een gebouw, op een bouwkavel, of binnen een hele wijk. Intensief ruimtegebruik heeft daarentegen een subjectief karakter, aangezien ieder individu intensiteit anders beleeft, en gaat over het aantal vierkante meters, dat per hectare grond wordt ontwikkeld. Dit wordt uitgedrukt in de floor space index. Ook intensief ruimtegebruik is mogelijk in de drie dimensies van ruimte en in tijd. Van alle strategieën van meervoudig en intensief ruimtegebruik zijn in hoofdstuk 2 praktijkvoorbeelden gegeven. Met meervoudig ruimtegebruik zijn door een optimale inrichting van de ruimte hogere residuele grondwaarden mogelijk en zijn er diverse maatschappelijke voordelen, waaronder het beschermen van de groene ruimte buiten de stad en het verminderen van milieubelasting, zoals het optimaliseren van transportkosten.

Om vastgoed te kunnen ontwikkelen bij en boven sporen in stationsgebieden is het van belang om inzicht te hebben in de specificaties van deze infrastructuur. Een vergelijking tussen Nederland en de omliggende landen laat zien dat Nederland per vierkante kilometer slechts een beperkt aantal kilometer spoor heeft liggen, terwijl deze sporen meer dan twee keer zo intensief gebruikt worden als de sporen in het buitenland. Het intensieve gebruik van deze sporen heeft behoorlijke consequenties voor de mogelijkheden om er overheen te bouwen aangezien er vanwege de intensiteit van gebruik veel hogere eisen worden gesteld aan de betrouwbaarheid en beschikbaarheid. In hoofdstuk 3 zijn daarnaast verschillende stationstypen gedefinieerd en hun impact op de mogelijkheden om de stad eromheen en erboven in te delen. De typologie van treinstations wordt bepaald door drie typen functionele inrichting (kopstation, doorvoerstation en kruisingstation) en vier verschillende hoogteliggingen (ondergronds, verdiept, maaiveld en verhoogd). Waar we in grote steden in het buitenland veel kopstations met sporen op maaiveld aantreffen (vooral bij voorbeeldprojecten), zien we in Nederland juist doorvoerstations met verhoogde sporen (daar waar grote projecten gepland zijn). Een doorvoerstation is moeilijker te overbouwen dan een kopstation, vanwege het veel intensievere gebruik van het spoor en een verhoogd spoor is moeilijker te overbouwen dan een spoor op maaiveld gezien de grote afstand die overbrugd moet worden tussen maaiveld en een eventueel kunstmatig maaiveld boven de sporen.

Voorbeeldprojecten

In de praktijk zijn reeds gebouwen ontwikkeld boven spoorinfrastructuur. Het oudste voor- beeld is de verbouwing van Grand Central Terminal in New York, waar begin vorige eeuw een bestaand station op maaiveld met stoomtreinen werd verbouwd tot een dubbel laags ondergronds station met geëlektrificeerde sporen. Daarbovenop werd ‘Terminal City’ ontwikkeld met onder andere het beroemde Waldorf-Astoria Hotel. Het drukste station ter wereld, Shinjuku Station in Tokio, wordt overbouwd en in Melbourne is het nieuwe culturele centrum Federation Square boven sporen gebouwd.

Ook in Europa zijn verschillende voorbeelden gerealiseerd. In hoofdstuk 4 is een zestal grote projecten op verschillende criteria geanalyseerd om inzicht te krijgen in de stand van zaken. In Londen is Liverpool Street Station overbouwd en worden plannen gemaakt voor de

262 Samenvatting

herontwikkeling van de King’s Cross Railway Lands. In Parijs is de Jardin Atlantique boven sporen gerealiseerd en wordt bij het project Seine Rive Gauche gewerkt aan de overbouwing van het spooremplacement van Gare d’Austerlitz. In Berlijn is dit jaar Lehrter Bahnhof, het centraal station, opgeleverd en binnen een paar jaar zal naar verwachting in Amsterdam gestart worden met het grootste project op het gebied van bouwen boven sporen, namelijk de Zuidas, waar 1 miljoen vierkante meter boven infrastructuur zal worden gebouwd.

Uit de analyse van de voorbeeldprojecten zijn interessante lessen te trekken. Bij de projecten wordt eerste de ruimte naast het spoor ontwikkeld, daarna wordt ruimte gemaakt voor nieuw vastgoed door de spoorinfrastructuur te optimaliseren en tenslotte wordt als sluitstuk de ruimte boven het spoor ontwikkeld. Ook blijken de projecten een vergelijkbare stedelijke dichtheid te hebben, waarbij de dichtheid bij kleinere projecten hoger ligt dan bij de grote projecten. Wat betreft meervoudig ruimtegebruik is te zien dat in de loop van de tijd bij deze projecten woningen en kantoren in een steeds gelijker verdeling worden ontwikkeld met ongeveer 10 tot 15 procent overige functies. Verschillen zijn gevonden in de verhouding waarmee publieke en private onderdeel uitmaken van de ontwikkelingsprocessen, in de huurniveaus en in de stedenbouwkundige concepten.

Een internationale vergelijking levert ook aandachtspunten op voor de Nederlandse praktijk. Een belangrijk verschil is bijvoorbeeld dat Nederlandse steden niet heel dicht bebouwd zijn, waardoor de grondprijs relatief laag is, met consequenties voor de haalbaarheid van complexe binnenstedelijke bouwprojecten. Nederlands ruimtegebrek speelt vooral op de schaal van het land als geheel. Een ander verschil is dat op een enkele uitzondering na Nederlandse stations doorvoerstations zijn, met een hogere capaciteit per spoor en daardoor minder flexibiliteit om er overheen te bouwen. Daarnaast brengt het netwerk van doorvoerstations ook met zich mee dat over deze sporen ook gevaarlijke stoffen worden vervoerd, waardoor externe veiligheid een belangrijke extra randvoorwaarde is.

Eisen voor bouwen boven sporen

Kwaliteit en flexibiliteit zijn belangrijke eisen wanneer vastgoed boven sporen wordt ontwikkeld. Wanneer perrons worden overbouwd wordt daglicht weggenomen en verandert een bovengronds perron in een ondergronds perron. Aan de hand van voorbeelden in Nederland en het buitenland is in hoofdstuk 5 getoond wat de consequenties kunnen zijn voor perrons op verschillende hoogten ten opzichte van maaiveld. Ook zijn middelen aangereikt om de negatieve effecten van de ‘ondergrondse’ ligging te compenseren, waaronder constructieve middelen, middelen in de samenhang van gebruik van daglicht en kunstlicht en middelen bij de afwerking van de ruimte. Naast de kwaliteit van de ruimte bij de infrastructuur heeft bouwen boven sporen consequenties voor de kwaliteit van het stedelijk gebied. De kwaliteit van de stedelijke ruimte is besproken aan de hand van de vijf stedelijke elementen die gezamenlijk de kwaliteit van het stedelijke gebied bepalen. Flexibiliteit is het vermogen van een ontwerp om ook in de toekomst te blijven voldoen aan de eisen die aan het gebruik gesteld worden. Flexibiliteit is nodig voor zowel de spoorinfrastructuur als de omliggende en bovenliggende stad. Vier typen flexibiliteit zijn behandeld: faseerbaarheid, onderhoudbaarheid,

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veranderbaarheid en uitbreidbaarheid. De eisen aan kwaliteit en flexibiliteit voor zowel stad als infrastructuur hebben invloed op elkaar. Als afsluiting van hoofdstuk 5 zijn afwegingen tussen deze eisen besproken.

Kwaliteit en flexibiliteit zijn relatief zachte technische eisen. In hoofdstuk 6 zijn de harde technische eisen besproken: geluid, trillingen en elektromagnetische compatibiliteit (EMC). Voor deze onderwerpen zijn wet- en regelgeving, specifieke problematiek van bouwen boven sporen en maatregelen bij de bron, de weg en de ontvanger beschreven. Het onderzoek naar geluid heeft zich specifiek gericht op de verticale geluidsafstraling van treinen. De gevels bevinden zich immers boven het spoor. Door de afschermende werking van het treingedeelte boven de wielen, ontstaat een substantiële reductie van de geluidsbelasting ten opzichte van de horizontale afstraling. Het onderzoek naar trillingen beschrijft specifiek de mogelijkheden om met constructieve maatregelen te komen tot voldoende trillingsbeperking. Onderzoek naar EMC beschouwt de maatregelen die voor de verschillende elektrische en magnetische velden genomen moeten worden om tot voldoende compatibiliteit te komen, i.e. geen gevaar voor de gezondheid en geen storing aan technische apparatuur. Ter afsluiting van de technische eisen is kort ingegaan op windhinder en luchtkwaliteit.

Veiligheid is ook een technische eis, maar door de grote invloed van veiligheid op het ontwerp, met name vanwege vervoer van gevaarlijke stoffen, is het onderwerp apart in hoofdstuk 7 beschreven. Veiligheid is met name voor bouwen boven sporen zo complex, omdat de kans op ongelukken door de veiligheid van het spoorsysteem zo klein is, terwijl de mogelijke gevolgen ervan weer zeer groot. Grote ongelukken met gevaarlijke stoffen op het spoor hebben zich in Nederland nog niet voorgedaan. Bijna-ongelukken geven echter aan dat het risico niet denkbeeldig is. Bij het ontwerp moet dan ook gezorgd worden dat de kans op ongelukken zo klein mogelijk is en dat voldoende voorzieningen genomen zijn om de gevolgen van een ongeluk zoveel mogelijk te beperken. Het onderzoek heeft zich voornamelijk gericht op externe veiligheid, het risico van transport over spoor voor de omwonenden. Hierbij is onderscheid gemaakt tussen het plaatsgebonden risico (gedefinieerd als een risicoafstand van het spoor) en groepsrisico, de kans op het overlijden van een gehele groep als gevolg van een ongeluk. Regelgeving voor plaatsgebonden risico maakt dat een zone van het spoor vrijgehouden moet worden en daardoor niet ontwikkeld kan worden. Omdat deze regelgeving tweedimensionaal is, kan de ruimte boven het spoor ook niet ontwikkeld worden. Regelgeving voor groepsrisico heeft minder specifiek effect op de zone vlak naast het spoor, maar bestrijkt een gebied tot tweehonderd meter van het spoor.

In hoofdstuk 7 wordt de HR-3D methode besproken. Deze methode is bedoeld als toevoe- ging op de huidige geaccepteerde computermodellen waarmee plaatsgebonden risico en groepsrisico worden berekend. De HR-3D methode splitst de verschillende typen ongelukken en stelt per type ongeluk maatregelen voor om gevolgen te beperken, waarmee beter wordt ingespeeld op de realiteit van de driedimensionale omgeving van bouwen bij en boven sporen, die met de bestaande modellen onvoldoende in beeld wordt gebracht. Om de werking van HR-3D te demonstreren zijn drie voorbeeldprojecten besproken op verschillende schaalniveaus; Piazza Center (gebouw), Dordrecht (spoorzone) en Amsterdam Zuidas (toekomstig stadscentrum).

264 Samenvatting

Constructief ontwerp

Bouwen boven sporen betekent dat verschillende maatsystemen gestapeld moeten worden. Enerzijds is er het maatsysteem van de spoorwegen. De minimale maat wordt bepaald door het profiel van vrije ruimte van de trein, maar de beschikbare ruimte voor constructies hangt daarnaast af van de ruimte tussen de sporen, noodzakelijke inspectiepaden en de aanwezigheid van perrons en wissels. In hoofdstuk 8 zijn vier locaties gedefinieerd waar boven sporen gebouwd kan worden; perrons, wisselstraten, parallelsporen en emplacementen. Ook de kantoren hebben standaard maatsystemen, opgebouwd uit veelvouden van 1,20 meter, wat leidt tot kantoormaten van 5,40 m, 6,00 m of 7,20 m. Voor dit onderzoek is een standaardkantoor van 43,20 m bij 14,40 m verder uitgewerkt. De lengte van 43,20 m is gekozen omdat hier zowel 6 keer 7,20 als 8 keer 5,40 m inpast zodat met verschillende overspanningslengten gevarieerd kan worden. De breedte van 14,40 m is gekozen omdat hier meerdere typen kantoorinrichtingen in mogelijk zijn.

Overbouwen kan met drie typen overbouwingsconstructies, die verschillen in de mate waarmee de gebouwen zich aanpassen aan de bouwruimte die door de sporen wordt opgelegd. De spoorstramienconstructie volgt het stramien van de sporen. Deze constructie wordt per verdiepingsvloer gestapeld, met mogelijk een afwijkende maat voor het kantoor. De overdrachtsconstructie is een constructie die het ongewenste stramien van het spoor omzet in een standaard stramien voor de kantoren. De overdrachtsconstructie functioneert als tussenlaag waarop een standaard gebouw kan worden gebouwd. Als derde is er de mega overdrachtsconstructie. Deze constructie gaat in een keer over het spoor en biedt ook de mogelijkheid om er een standaard stramien voor kantoren in te gebruiken. De mega overdrachtsconstructie onderscheidt zich van de overdrachtsconstructie doordat bij de mega overdrachtsconstructie de constructie meer dan de helft van de gebouwhoogte inneemt. Voor alle drie de typen overbouwingsconstructies is de invloed op kwaliteit, flexibiliteit, technische aspecten en veiligheid besproken.

In hoofdstuk 8 zijn vervolgens de ontwerpoverwegingen besproken voor het constructief ontwerp van een gebouw van sporen. De concrete invulling ervan zal overigens altijd samenhangen met lokale randvoorwaarden. Bij het ontwerp is de lengte van de primaire overspanning van belang. Eventueel kan de primaire overspanning in de lengterichting van het spoor worden gekozen als de secundaire overspanning over het spoor met een vloer mogelijk is. Naast de overspanningslengte en –richting is ingegaan op overwegingen voor het oplossen van de stabiliteit van de constructie van het spoor en de overwegingen voor de fundering, specifiek gericht op de verschillende mogelijke hoogteliggingen van het spoor. Ook is de keuze voor verschillende materialen voor de hoofddraagconstructie besproken en de mogelijkheden om gebouwen boven sporen functioneel met maaiveld te verbinden. Als laatste onderwerp voor het constructief ontwerp zijn de randvoorwaarden van het bouwproces beschreven. Om in hoofdstuk 9 de financiële haalbaarheid van bouwen boven sporen te kunnen bepalen zijn ter afsluiting van hoofdstuk 8 de kosten van de hoofddraagconstructie bepaald ten opzichte van een standaard kantoor. Dit is gedaan voor zowel de spoorstramienconstructie als de overdrachtsconstructie. Hierbij is gevarieerd met overbouwingslengten, oriëntatie ten opzichte van de sporen en het aantal verdiepingen.

265 Rail Estate

Financiële haalbaarheid

Bouwen boven sporen is financieel haalbaar wanneer de luchtrechten boven sporen een positieve waarde hebben. Voor het bepalen van de waarde van de luchtrechten is een vergelijking gemaakt met vastgoed naast sporen. Bij vastgoed naast sporen bestaan de investeringskosten uit de kosten voor het gebouw en de kosten voor de grond waar het gebouw op is ontwikkeld. De grondkosten zijn bepaald aan de hand van de residuele waarde van de grond; de mogelijke opbrengsten van een gebouw minus de kosten voor het realiseren van dat gebouw zelf. Bij een gebouw boven sporen bestaan de investeringskosten uit de kosten voor het gebouw en de kosten voor de luchtrechten. De kosten voor een gebouw boven sporen zijn vergeleken met de kosten voor een gebouw naast de sporen. De meerkosten van bouwen boven sporen zijn aangegeven als minimale en maximale waarde als percentage van de kosten van een standaard gebouw naast de sporen. Er is een spreiding aangegeven omdat de werkelijke kosten afhangen van de locatie. Voor gebouwen naast sporen is op basis van referenties onderzocht wat de mogelijke kosten voor de grond ten opzichte van de kosten voor het gebouw zijn. Onderzoek naar de opbrengsten van gebouwen boven sporen ten opzichte van gebouwen naast sporen laat zien dat er geen hogere huuropbrengsten of betere bruto aanvangsrendementen te verwachten zijn. Er zijn voor gebouwen boven sporen wel extra aandachtspunten, maar aangenomen kan worden dat de opbrengsten vergelijkbaar zijn. Op basis van de spreiding in de kosten van de grond voor gebouwen naast sporen en de spreiding van de extra kosten voor de realisatie van gebouwen boven sporen is een gebied vast te stellen waar de luchtrechten een positieve waarde hebben en bouwen boven sporen dus haalbaar is.

Afsluitend

Dit promotieonderzoek heeft zich gericht op de technische en financiële haalbaarheid van bouwen boven sporen. Alle technische aspecten van bouwen boven sporen zijn behandeld. Wanneer integraal wordt ontworpen en met alle complexe randvoorwaarden die de spoorinfrastructuur oplegt rekening wordt gehouden is bouwen boven sporen technisch zeker mogelijk. De vraag naar de financiële haalbaarheid ervan is echter minder eenduidig te beantwoorden. Residuele grondwaarden, die de basis vormen voor het bepalen van een mogelijke positieve waarde van de luchtrechten boven het spoor, kennen een ruime spreiding. Het onderzoek heeft echter laten zien dat ook de extra kosten voor bouwen boven sporen een flinke spreiding kennen, afhankelijk van de locatie. De zoektocht naar locaties waar bouwen boven sporen haalbaar zou kunnen zijn zal dus in ieder geval verder moeten gaan dan het zoeken naar locaties met een hoge grondprijs. De financieel ideale locatie voor bouwen boven sporen bestaat namelijk uit een optimum van minimale technische complexiteit en maximale grondwaarde.

266 Introduction

About the author

Sebastiaan de Wilde was born in Amsterdam on 6 October 1976. In 1994, after obtaining the Dutch equivalent of A-levels at St Ignatius Gymnasium in his home town, he began studying civil engineering at Delft University of Technology. Beside civil engineering, he also embarked on a business studies degree at Erasmus University Rotterdam in 1996. For his civil engineering degree, he decided to specialize in structural and building engineering, graduating in 2000 with a final project that involved designing an over-track structure for the sidings at Den Haag Centraal station. He conducted that study at Holland Railconsult (now Movares). Sebastiaan specialized in financial management for his business studies degree, graduating in March 2001 with Cees Luijendijk at ING Real Estate, with a study on residual value risk in property leasing.

Since April 2001, Sebastiaan has been working full time in Movares’ structural design department while completing his doctorate. He has therefore had two roles – consultant and doctoral student. In his capacity as a consultant, he was one of the driving forces behind the development of the Stapeldok model for the Amsterdam Zuidas project. He also worked on various projects involving property development near and over railway tracks. As a researcher, he has published over 50 articles in journals, at international congresses and in the specialist press. He has already published his thesis in abbreviated form (in Dutch), in four separate parts. Both as a consultant and as a doctoral student, Sebastiaan has given a number of presentations in the Netherlands and abroad, at congresses and workshops.

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268 Introduction

Acknowledgements

Promoveren doe je niet alleen. Ik wil hier dan ook al diegenen bedanken die hebben bijgedragen aan de totstandkoming van dit proefschrift. Met name door het multidisciplinaire karakter van het onderzoek zijn er velen waarmee ik ideeën en overwegingen heb kunnen delen en die mij met hun vakkennis van informatie hebben voorzien.

Als eerste gaat mijn dank uit naar Movares, dat bereid is geweest om mijn promotietraject te financieren. Dit is in de praktijk van adviesbureaus namelijk heel bijzonder. Voor de begeleiding en financiering gaat ook dank uit naar René Buvelot van ProRail. ProRail heeft substantieel bijgedragen in de kosten van het onderzoek en specifiek wat betreft de Nederlandse weerslag daarvan in een viertal publicaties.

Dank gaat ook uit naar mijn promotoren Jan Vambersky en Ed Nozeman voor het delen van hun kennis en hun inzet om mij uit te blijven dagen om een steeds hoger niveau te halen bij het uitvoeren van mijn onderzoek. Ook de andere leden van de promotiecommissie wil ik hier graag bedanken voor hun bereidheid om in deze commissie zitting te nemen. László Vákár wil ik speciaal bedanken voor zijn inzet om een promotieplaats binnen Movares te organiseren en het vertrouwen dat ik deze taak met goed gevolg zou volbrengen. Op vele vlakken heb ik van hem de afgelopen jaren kunnen leren en heb ik met veel plezier binnen de afdeling Constructief Ontwerpen kunnen werken.

Voor de verschillende onderdelen van het proefschrift hebben experts met hun specifieke vakkennis bijgedragen. Bedankt Sonja Riemersma (voor je hulp bij de methodologische aspecten van het onderzoek), Andy van den Dobbelsteen (voor het samen uitwerken van de ideeën en de typologieën van meervoudig en intensief ruimtegebruik), Paul Chorus (voor de informatie over Japan), Ita Luten, Rob Stringa, Kees Peters en Edwin Megens (voor alle informatie en reflectie op de complexe aspecten kwaliteit en flexibiliteit), Bert Paanakker en Phlip van den Dool (voor alle informatie over geluidhinder), Herke Stuit en Bas Kuiper (voor de informatie over trillingshinder), Maurice Janssen (voor je hulp bij het ontrafelen van de

269 Rail Estate

problematiek van elektromagnetische compatibiliteit), Harry Snel en Bas Ropers (voor het ontwikkelen van de HR-3D methode), Paul van de Ven (voor je reflecties op de ontwikkelde ideeën voor fysieke veiligheid), Melvin Eschweiler, Eric Kool, Jan Matthijs van der Waal en Jan Faber (voor jullie steun en input bij de uitwerking van de verschillende typen overbouwingsconstructies) en bedankt Robert Cijs, Ruud Weterman, Kees van Elst en Bart Louw (voor de informatie en ideeën voor het onderbouwen van de financiële beoordeling van bouwen boven sporen).

Ook degenen die bereid zijn geweest om binnen het kader van mijn onderzoek af te studeren wil ik bedanken. Met hun onderzoek hebben ze allen puzzelstukjes aangeleverd voor dit proefschrift. Op volgorde van afstuderen: Shahid Suddle (Veiligheid van bouwen bij meervoudig ruimtegebruik), Sander Stolk (Hoogbouwontwerp in Rotterdam centrum boven Schiekade en spoorwegviaduct), Stef Jacobs (Geluidhinder bij bouwen boven sporen), Erik Kokken (Flexibiliteit bij spoorwegoverbouwingen), Leon Langeweg (Brandveiligheid van spoorwegoverbouwingen) en Tom Hoekveld (Ontwikkeling woongebouw boven spoorgebied).

Omdat het zo belangrijk is geweest om tijdens het onderzoek met medepromovendi van gedachten te kunnen wisselen over onderzoeksopzet, onderzoeksfocus en meervoudig ruimtegebruik in het algemeen wil ik graag de leden van de onderzoeksgroep meervoudig ruimtegebruik bedanken: Caroline Rodenburg (VU), Ron Vreeker (VU), Karst Geurs (UU), Shahid Suddle (TUD), Jan Jacob Trip (TUD), Stan Majoor (UvA) en begeleiders Erik Louw (TUD) en Frank Bruinsma (VU).

Het boek zelf was nooit zo goed leesbaar geweest en had er nooit zo mooi uitgezien zonder de inzet van Steve en Steef. Steve Rawcliffe, bedankt voor het bewerken van mijn Engelse teksten en je geduld om daar met alle precisie tot en met de vaktermen mee om te gaan. Steef, bedankt voor het zorg dragen voor het integraal ontwerp van het boek en daarmee voor de algehele uitstraling en bedankt voor je flexibiliteit om er ook meerdere avonden aan te willen doorwerken. Edwin Megens, bedankt voor de technische tekeningen in hoofdstuk 8 en je bijdrage aan de discussies over het grafisch ontwerp. Nathalie Lansbergen, jij ook bedankt voor je reflecties op en bijdrage aan het grafisch ontwerp. Marc Klamer, tenslotte, bedankt voor je bijdrage aan de laatste slag van beeldscherm naar boek.

Naast de bovenstaande betrokkenen hebben een aantal anderen een belangrijke rol gespeeld de afgelopen jaren. Marleen Peeters, bedankt voor al je reflecties op mijn teksten en de lessen op het gebied van tekstschrijven. Michiel Smit, bedankt voor de samenwerking bij de artikelen in de Nova Terra waarmee ik mijn onderzoek mede heb kunnen profileren. Jan Garvelink, in jouw tijd als divisiedirecteur bij Stedelijke Knooppunten heb je me veel inspiratie gegeven en de moeite die je hebt genomen om mijn proefschrift integraal van commentaar te voorzien heb ik zeer gewaardeerd. Harry Snel, ook buiten het onderzoek naar externe veiligheid en de gezamenlijke ontwikkeling van de HR-3D methode is werken met jou een feest van creatief denken, dank voor al je betrokkenheid. Paul Witteman, ik heb genoten van onze samenwerking (vooral aan Stapeldok), ons dagelijkse cola overleg en de vele treinreizen. Gert Visser, bedankt voor alle bemoedigende gesprekken en kritische

270 Acknowledgements

reflecties, ik heb een hoop opgestoken van al onze gesprekken aan het einde van de dag en vaak begin van de avond. Andy van den Dobbelsteen, als collega promovendus heb ik grote steun aan je gehad en het was leuk dat onze onderzoeken voldoende raakvlakken hadden om te kunnen samenwerken.

Mijn collega’s van Movares, en speciaal de directe collega’s van Constructief Ontwerpen, wil ik bedanken voor de leuke tijd tijdens het promotietraject. Ook de collega’s van Gebouwen en Bouwtechniek (inmiddels Building Engineering) aan de faculteit Civiele Techniek van de TU Delft wil ik bedanken, en speciaal Anneke Meijer. Ook dank aan al diegenen buiten Movares en de TU Delft die de afgelopen jaren bereid waren om met mij van gedachten te wisselen over het onderzoek.

Zeer speciale dank gaat uit naar Eric Kool en Edwin Megens. Eric, de afgelopen jaren als kamergenoten waren geweldig en ik wil je bedanken voor alle gezelligheid en goede zorgen. Edwin, samenwerken met jou de afgelopen jaren heeft veel voor mij betekend. We hebben mooie projecten gedaan en je bent als vriend zeer betrokken geweest bij de totstandkoming van dit boek. Paranimfen Melvin Eschweiler en Jeroen de Wilde, bedankt dat jullie naast mij willen staan wanneer ik het onderzoek tegenover de commissie verdedig, Melvin daarnaast speciaal ook voor je bijdrage aan het proefschrift.

Tenslotte wil ik mijn familie en vrienden bedanken voor alles. Ik hoop met jullie allen 12 december het glas te heffen en er een leuk feestje van te maken. Ook Nicole, bedankt voor je liefde en zorg. En als laatste Theo en Hilde, jullie hebben alle randvoorwaarden verzorgd waardoor ik me altijd optimaal heb kunnen ontwikkelen. Zonder jullie stimulans was dit proefschrift er niet geweest. Bedankt voor jullie liefde en alle kansen die jullie me hebben gegeven.

271

The demand for new development sites, coupled with a wish to preserve green areas outside cities, is provoking increasing interest in inner-city redevelopment. All over Europe, projects of multiple use of space are appearing that involve developing high-quality buildings in which to live and work, while taking account of the history of the city concerned. Station locations occupy a very specific position within this urban construction trend. They are of particular interest on account of their being readily accessible, not only by train but also by other forms of public transport. These locations are also sited close to all urban facilities. But the very quality of these locations lies at the root of their problems. Because of their strategic positioning, numerous parties are involved in decision making, and those parties have differing interests. Furthermore, the proximity of railway infrastructure means that a large number of environmental regulations must be complied with. The complexity of the rules is one reason why much space near stations is still undeveloped. Often, this space is occupied by low value industry, and also railway infrastructure occupies a large percentage, in the form of sidings and yards. The present thesis examines the possibilities that exist for building over railway infrastructure. In other words, for developing Rail Estate.