Engineering Tall in Historic Cities: the Shard
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ctbuh.org/papers Title: Engineering Tall in Historic Cities: The Shard Authors: Kamran Moazami, Director, Head of Building Structures, WSP Group Ron Slade, Director, WSP Group Subject: Structural Engineering Keywords: BIM Structural Engineering Publication Date: 2013 Original Publication: CTBUH Journal, 2013 Issue II Paper Type: 1. Book chapter/Part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished © Council on Tall Buildings and Urban Habitat / Kamran Moazami; Ron Slade Structural Engineering Engineering Tall in Historic Cities: The Shard Can historic cities preserve their character and identity while embracing the modern tall building phenomenon? Two engineering-team leaders behind the Shard discuss the creative solutions needed to insert a massive project into the dense historic and infrastructural fabric of London. The Shard and The Place at London Bridge One of the key challenges of building tall in (see Figure 1), projects by developer Sellar historic cities is keeping streetscapes Kamran Moazami Ron Slade Properties / Qatari Diar and architect Renzo permeable and delicate. Certainly, tall Piano, demonstrate the special challenges buildings require large cores and huge Authors faced by engineers and architects to preserve columns to take lateral and gravity forces, but Kamran Moazami, Director, Head of Building Structures and develop the character of historic cities, they must also respect people and public Ron Slade, Director while properly embracing the tall building spaces at street level. Historically architectural WSP UK phenomenon. Both buildings work within the development has not paid suffi cient attention WSP House, 70 Chancery Lane London WC2A 1AF ancient street pattern of Southwark and to the interface of tall buildings and life at United Kingdom demonstrate how modern development can ground level. Now it is generally accepted by t: +44 20 7314 4654 add new life to an area without destroying the the best designers that the eff ect at street f: +44 20 7314 5111 local environment. Southwark, like other parts level is equally as important as the impact on e: [email protected]; [email protected] of London, suff ered heavy damage during the the skyline, and is critical to a project’s www.wspgroup.co.uk Second World War, but retained its historic integration into the culture and lifeblood of a street layout. In fact, the shape of The Shard city. Kamran Moazami site was created by bombing during the war. With over 33 years of structural engineering experience, Kamran works between the United In recent decades, the planet has urbanized Kingdom and United States, ensuring that clients The site was redeveloped in 1975 by the on an unprecedented scale. We need to involved in property development derive the full benefi t of WSP’s internationally renowned, specialist construction of a rather insensitive, inward- create cities that can cope with these expertise in structural engineering. looking building, but now, with the help of demographic changes and accommodate the Kamran received his BSCE and MSCE from Columbia far-sighted designers, the new buildings are inevitable pressure on transport, energy, University and his professional engineering licences in New York. In 1989 he set up WSP Cantor Seinuk’s on the verge of changing the whole area into water, and living spaces. In an age when more London offi ce and since then has been involved in an iconic part of London, adding to the rich than half the world’s population lives in cities, more than 20 million square feet of mostly specialist structures throughout the United Kingdom. He texture of the neighborhood, rather than there is more demand than ever for space. Tall has also been involved in masterplanning and detracting from it. It was no accident that buildings off er the most effi cient use of land; development of such prestigious projects as Canary Wharf, Wood Wharf and Bishopsgate Good’s Yard. Renzo Piano acknowledged the history of building up, rather than out, must be part of London and the local area in his planning the solution. It is part of the responsibility of Ron Slade submission by referring to the infl uence of engineers to design the structure of tall Ron received his BSc in Civil Engineering at City 17th-century church and cathedral spires. buildings so that they meet the various needs University, London and became a chartered member of the Institution of Structural Engineers in 1971, when he was awarded the Institution’s A. E. Wynn prize. He was fi rst appointed as a director in 1982. Ron has special expertise in construction forms and methodologies and materials use. He has been involved in a wide range of jobs in various sectors, on both new-build and refurbishment projects. Over the past 13 years, Ron has specialized in high-rise construction. His recent work includes concept design for several London projects, including both the Shard and the Place at London Bridge, and the Milton Court development, which incorporates the Guildhall School of Music and Drama. Ron has published papers in The Structural Engineer, Civil Engineering and elsewhere and chairs WSP’s Technical Strategy Group for structural engineering for the advancement of technical knowledge and design skills. Figure 1. The Shard & The Place at London Bridge. © Sailko 44 | Structural Engineering CTBUH Journal | 2013 Issue II Figure 2. The Shard – winter garden. © Renzo Piano Building Workshop Figure 3. Existing and new piles at the Shard. © WSP of the urban population in a fl exible and for tenants. These spaces are outside the under-reamed piles founded in the London responsible way. Consequently, the challenges double-glazed part of the façade, but within clay. They extended only a few meters below for the engineer are numerous. the outer single-glazed skin. Ventilation allows The Shard basement slab, and so could not be fresh air into these spaces, and the steelwork reused to provide vertical support for the new detailing is visually enhanced and left on view building. It was not economical to remove the The Right Streetscape (see Figure 2). old piles, so the new piles were designed to pass between the old ones and their under- In the past, street design has not been a By breaking away from the standard, risk-averse reams (see Figure 3). priority for all stakeholders – the net result is approach to design, and instead following a that tall buildings have been planted on sites rational and creative process, we can achieve Existing piles were not the only constraint to without due regard for their surroundings. By high-quality places that embrace modern tall be dealt with at the Shard. Other existing engaging in a diff erent approach, through an building design. This leads to large buildings infrastructure in the vicinity included London evolving and collaborative process with that sit comfortably alongside buildings from Underground’s Jubilee line tunnels, which were professional designers and enlightened key diff erent ages. Instead of dominating historical about 5–10 meters from the northwestern stakeholders, a robust and respectful result is cities, they will complement and contribute to corner of the Shard basement, a disused stair achievable. Analyzing diff erent street the development of our cities in a way that shaft inside the site, a disused lift shaft typologies and public realm treatments and preserves and enhances urban character. In straddling the boundary, and a ventilation shaft assessing capacity for pedestrians, public well-considered schemes, all applicable to the west, in Joiner Street. The adjacent transport, and traffi c now contributes to engineering disciplines will have studied traffi c streets also contained the usual sewers, balanced streetscapes, in terms of movement and pedestrian fl ows, wind comfort, and the Victorian water mains, and other utilities. and the psychological perception of tall permeability of structures at ground level. buildings. Creating good-sized fl oor plates in the tower Dealing with a Spider’s Web of Existing called for some clever structural solutions and The concept of the “vertical city” is gaining Underground Infrastructure meant building as close as possible to the acceptance, resulting in more mixed-use tall underground infrastructure. Limiting ground buildings in recent years. The Shard recognized Unlike building on clean sites in suburban movement was critical to protect London that tall buildings need to deliver places that areas, building on historic inner city sites often Underground’s assets and to ensure no people enjoy for living, leisure, and shopping, has inherited complexities that must be damage occurred to the water main. Therefore, as well as for working. The wider economic, considered. New development is constrained 3D fi nite element analysis was used to predict social, and environmental benefi ts of tall by a spider’s web of ground-level and potential ground movement and convince the buildings set in a good public realm is beyond underground infrastructure, which presents statutory bodies that it was safe to work within question. A well-positioned tall building has a enormous challenges to the designer. sensitive close-proximity zones. regenerative eff ect on its surroundings. The Shard foundations in London were aff ected Movement monitoring, vibration, groundwater In some instances, the streetscape can be by the piles left in the ground from Southwark mitigation and possible re-use of old piles were taken into the buildings. At the Shard, each Towers, a 26-story reinforced concrete building taken into account in the design of the Place as offi ce fl oor is provided with three winter constructed in the 1970s. This building had no well as the Shard. These factors aff ect many gardens in order to improve the environment signifi cant basement, and was supported on other developments in London and elsewhere. CTBUH Journal | 2013 Issue II Structural Engineering | 45 Made ground +4.7 m OD to 0.0 m OD techniques were used to adjust plant circumvented.