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Olympics Images on this page Courtesy of BurlandTM The roof of the main stadium would be lowered to would twist the fabric in two directions, keeping suit the new size, but leaving enough space to re-fit it tensioned and giving it stiffness,” says Mr King. the second tier of seating and take the capacity back The only additional support would be cables along up to 45,000 if needed. It would be possible to re- the valleys and ridges, and a circumferential cable erect the removed seating as part of another venue around the inside edge forming a tension ring. Above: Cutaway elsewhere in Britain. The folded shape would also facilitate drainage of axonometric view. The Involving a steelwork contractor at an early stage rainwater to the outer edge. folded fabric roof would delivered significant benefits for an even more The seating terrace frame structures would be be supported by a cable radical design which has been proposed by James made from steel sections, each element being tension ring at its inner edge. The seating units Burland and Mike King, who were respectively around 8m–12m long, assembled in segments would be constructed Project Design Director and Structural Engineer on independently of the in segments outside the the City of Manchester stadium, which could be “We would use steel roof, and slid into stadium and slid into their completely dismantled and moved after the Games. because its strength their final position. final position. Mr Burland, formerly Head of Design at “The geometry would Arup Associates and now head of his own firm to weight ratio is be repetitive and as BurlandTM, and Mr King, an Associate at Arup, better than anything simple as possible,” brought in Watson Steel Structures to advise on says Mr King. “We else commercially practical issues. Watson had erected the Manchester would use steel stadium roof and before that the Millennium Dome, viable at present.” because its strength to Their original idea was for a conventionally- weight ratio is better shaped stadium with an oval playing area contained than anything else commercially viable at present.” within a structure with a rectangular footprint. For the seating itself, Burland and King propose “Watson’s advised us that we needed something using folded aluminium units spanning between Below: A cutaway really repetitive,” says Mr Burland. This led to the the steel members. “Normally you’d use precast rendering of the stadium idea of a circular structure which provides a constant concrete, but with anything built in concrete it’s Bottom: Plan of stadium radius for the seating terraces, giving the necessary difficult to argue it’s transportable,” says Mr King. shows the profile of the repetition. Prefabricated pods for toilets and washrooms fabric roof. The circular The seating terraces would be at a fairly steep would be added outside the stadium, and the whole form of the stadium allows rake of 42 deg to keep the structure as compact as structure would be ‘dressed’ by a simple additional the seating terraces to be structurally repetitive. possible and provide good sightlines. Inset seating square structure around it to provide an entrance for VIPs and media would be provided along the foyer, ticket barriers and so on. This would not be long side of the track in front of the main seating an integral part of the scheme, though a similar idea tiers. with signage and banners to suit could be applied on A cable net roof would be used as at the subsequent uses. The cladding of the compression Manchester stadium. The main structural element ring could also be changed as appropriate. in the design is a huge compression ring around Burland and King’s target cost had been £100M the exterior, supported on large diameter tubular- for an 80,000 seater stadium; the eventual design core structures which also form the basis of spiral has been costed at £120M, which is still an economic entrance ramps. The ring, a diagrid structure price. Mr Burland pays tribute to the assistance of made up of universal column sections, would be Watson Steel Structures in developing a practical three storeys deep and could provide 29,000m2 of design, and EC Harris in costing it. floor space. With its supports, it could be built in After the Games the vacant site could be given advance to house offices for the Olympic organising over to mixed used development, using the committee before and during the Games as well as drainage, roads and other infrastructure put in place VIP facilities, a media centre and other facilities. for the stadium. “We will put in a bid for 2012 when The ring could be pre fabricated — and fitted out the stadium goes to tender,” says Mr Burland. “It — offsite or on the ground and winched or jacked up would be terrific to have something to gift to Africa. the columns. For transport to a new location it would The regeneration effect of staging the Olympics be broken down into modular units. there would be incredible.” The roof canopy would be a lightweight, translucent fabric folded into a zig-zag shape along (This article is a shortened version of one that first the outer edge, but flat at the inner edge. “This appeared in Structural Engineer 1 November 2005) 14 NSC January 2006


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