THE ART OF PRECAST CONCRETE THE ART OF PRECAST CONCRETE COLOUR TEXTURE EXPRESSION COLOUR TEXTUREEXPRESSION THE ART OF PRECAST CONCRETE David Bennett Basel ·BerlinBoston Birkhäuser –PublishersforArchitecture We would like to thank the following institutions who kindly supported this publication: Aalborg Portland, Aalborg, Denmark Betongvaruindustrin, Danderyd, Sweden Bundesverband der Deutschen Zementindustrie e.V., Berlin, Germany Lafarge, Paris, France Rakennusteollisuus, Helsinki, Finland The Concrete Centre, Camberley, England Graphic design: Alexandra Zöller, Berlin Parts of “Precast Materials and Methods of Manufacture” are derived from the essay “Cast Reconstructed Stone” written by David Bennett for the publication Christoph Mäckler (ed.), Material Stone: Constructions and Technologies for Contemporary Architecture, Basel: Birkhäuser, 2004. A CIP catalogue record for this book is available from the Library of Congress, Washington D.C., USA Bibliographic information published by Die Deutsche Bibliothek Die Deutsche Bibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data is available in the internet at http://dnb.ddb.de. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data banks. For any kind of use, permission of the copyright owner must be obtained. © 2005 Birkhäuser – Publishers for Architecture, P.O. Box 133, CH-4010 Basel, Switzerland Part of Springer Science+Business Media Printed on acid-free paper produced from chlorine-free pulp. TCF ' Printed in Germany ISBN-13: 978-3-7643-7150-0 ISBN-10: 7643-7150-1 9 8 7 6 5 4 3 2 1 www.birkhauser.ch CONTENTS Preface 6 Precast Materials and Methods of Manufacture Dry Cast Concrete 8 Wet Cast Concrete 9 Self-Compacting Concrete (SCC) 11 Sandwich Panel Construction 11 Precast Light Concrete 12 Precast Ultra Concrete 14 Types of Surface Finishes 17 Support and Fixings 20 Cost and Construction Matters 21 Denmark Spæncom Visitor Centre and Main Office, Aalborg 24 Grammar School, Nærum 28 SID Building, Århus 34 United Exhibits Group Headquarters, Copenhagen 40 Finland Main Building, University of Oulu 44 Saterinrinne Housing Development, Helsinki 50 Rastipuisto Apartment Block, Helsinki 54 Mustakivi School and Community Centre, Helsinki 60 France 9 Avenue René Coty, Paris 66 École Maternelle, Paris 70 A16 Motorway Toll Booths, Picardy 76 Germany Headquarters of Sozialverband Deutschland, Berlin 80 Scharnhauser Park, Ostfildern 86 Synagogue and Community Centre, Dresden 90 Mexican Embassy, Berlin 96 Great Britain 10 Crown Place, London 102 35 Homer Road, Solihull 108 Experian Data Centre, Nottingham 114 Scottish Parliament Building, Edinburgh 120 Sweden Arlanda Control Tower, Stockholm 126 Henry Dunkers Cultural Centre, Helsinborg 130 Katson Building, Stockholm 136 Geological and Geographic Sciences Building, Stockholm 142 Glass Fibre Reinforced Concrete Stadtvilla Apartments, Kassel 146 25-35 Park Lane, London 148 Compact Reinforced Composite Spiral Staircase, Copenhagen 152 Ductal® Seonyu Footbridge, Seoul 156 Useful Contacts 160 Illustration Credits PREFACE The Brutalist period that followed the Modern Movement era, where cast in place concrete was used to excess, led to decades of mistrust and rejection of its architectural merit as the rust stained, grey-black, pock marked surfaces were laid bare for all to witness. Precast concrete up to that time was largely specified for making reconstructed stone panels, paving slabs and decorative features. Now it was used as the replacement for cast in place concrete in many European countries, ensuring the integrity of surface appearance with off-site manufacture. Precast concrete’s popularity grew, the product range increased and many new precast companies started up. Colour, surface texture, light and shade profiling and bas relief effects plus plasticity of form and large panel construction gave architects a design freedom that was not possible with cast in place concrete. Better material understanding, researches into surface durability, improved standards of manufacture and production continues to position precast concrete as the premier product for surface appearance in Northern Europe but it comes with a warning. It can be prohibitively expensive in some countries and is not always a popular choice. In today’s building markets, reflected by its share of the architectural cladding market, popularity of precast concrete varies dramatically across Europe. In the UK for example it is considered the most expensive, heavy-weight cladding option for a façade. Its market share is less than 2% of the cladding market. In Finland precast concrete takes 33% of the total building market and is the most dominant material for cladding multi-storey residential buildings (97%) because it is the cheapest and most efficient method of construction. Precast market situations in Sweden and Denmark echo the trend in Finland. In researching the material for this book this startling difference in market share became all too transparent. Market share is higher where the price of precast cladding panels is low or competitive with alternatives – that is obvious. What is not are the reasons for these big differences. In Finland to keep precast prices competitive architects and specifiers must choose standard products from manufacturer catalogues. To do otherwise would incur large surcharges of up to 300% for bespoke production. The design of precast structural and façade elements is carried out by structural engineers and architects working to guidelines given in the precast product literature. The precast manufacturer concentrates solely on the production and supply of units to the site. They use flat bed casting methods that are semi-automated and highly mechanised, employing the minimum of labour to keep costs down. The precast prices are based on high volumes and standardisation of the product range. They are not involved in the site assembly and erection of precast units. That is carried out by the main contractor who is familiar with precast composite construction. The preferred choice of construction of residential buildings in Finland is precast floor planks with precast load-bearing façade panels. When looking at residential architecture in Finland you become aware of the similarity of composition, the standardisation of façade panel construction and how creative architects can be within these tight parameters: a very compelling argument that good design need not be expensive. 6 By contrast the architectural cladding market in the UK is the total opposite. There is no standardisation of façade elements industrywide or from one project to the next. Architects and designers are free to scheme their layouts, unique to their own project. They are encouraged to use the same panel unit and assembly arrangement to reduce the cost of mould making, but that is often not possible. The façade units are designed by the precast company who usually erect and assemble the units as a total supply and install package. Consequently the precast company will carry a lot more overheads and risk. By encouraging bespoke, non- standard units to be specified, they attract a much higher price in production. Each precast company will have their own connection detail and fixing arrangements. As a result we see exuberance, expressive and flamboyant architecture that comes at a price premium, but there are examples where restraint and rigour has given a fine quality to the structure. They all have one thing in common – they are all different and that perhaps is the telling attraction and appeal of British precast architecture. As a result of these divergent market conditions, the architecture will differ in scope and aspirations from one country to the next. Precast design reflects the economic constraints on local production as much as the self-conscious attempts by architects to imbue artistic endeavour, context, creative inspiration and ordered formality into the functional purpose of a building. This collection of projects from Sweden, Denmark, Finland, France, Germany, Scotland and England shows how precast concrete in all its different forms, modes and finishes can be brought together creatively and thoughtfully. Some make use of bold vibrant colours and shapes, some draw expression from restraint and tautness of standardised components, while others show how light-weight glass fibre reinforced concrete and the new ultra high strength precast CRC and Ductal® products offer new possibilities in precast architecture. Each project has been reviewed as a case study with illustrations and descriptions on how it was designed and built and how the precast elements were specified. While the examples are not a definitive list, they have been recognised for their excellence of concrete expression. The section on materials and methods will provide the reader with information on the many different ways to precast concrete and the many choices of surface finish, texture and profiling that are possible. I am indebted to all the architects and precast manufacturers who gave up their time to share their knowledge with me. I wish to thank those organisations and individuals who helped to make the research to this book possible by arranging my visits to each country. They are BDZ and Jörg Fehlhaber in Berlin, Betongvaru-