Project Analysis Of New Wembley Stadium
The construction of the new Wembley stadium is a project which has been both controversial and fascinating. The aim of the project was to design and build a state-of-the-art national stadium, unlike any other in the world, to be the home of English football and to host large events such as Cup Finals, music events and athletics. The new stadium is eventually expected to become an icon in the same way as the old stadium with the twin towers replaced by the arch.
The new 90,000 all-seat stadium will be operated by WembleyNational Stadium Ltd (WNSL) and is now expected to be finished and signed off by late summer 2006, ready to host its first events in 2007 (following a block of event cancellations in 2006). The old stadium was closed in 2000 and demolished in 2002. Construction of the new stadium began in October 2002.
FINANCE OF THE NEW STADIUM
To overcome financial concerns over the new stadium, the parties involved came to an agreement on a fixed-cost contract. This made provision for a building cost of around £352 million, with total projectcosts of £757 million.
Under such an arrangement, the client is protected from exposure to budget over-runs or delays in construction. That risk is borne by the main contractor; Multiplex (UK) Ltd. Cyril Sweett acted as independent consultants for WNSL in April 2002 and cleared the Multiplex contract as representing value for money. A National Lottery fund investment of £120 million was made into the stadium. Financial backing of £426 million for theproject was secured through West Deutsche Landesbank of Germany. Ken Livingston and Brent Council secured £21 million in funding for the project and a further £17.2 million from WNSL for improvements to transport infrastructure in the area around the stadium. The stadium will be linked to Wembley Park Station (London Underground) via Olympic Way and also WembleyCentral Station via the White Horse bridge. The stadium has now also triggered a major regeneration scheme in the surrounding area. Nathaniel Lichfield and Partners was the planning consultant for the project.
DESIGN AND ARCHITECTURE
The design (50 year design life) of the new stadium is both functional and architecturally significant. Sir Norman Foster designed the arch and the roof structure, with the remainder of the stadium being designed by architects Foster and Partners and HOK Sport. The stadium’s unique features include retractable roof panels and the arch. These were developed in response to the particular requirements of the stadium, one of which was the need for a high-quality grass pitch in order to achieve UEFA 5 star stadium status. By using retractable roof panels, which retract to the south, it allows as much daylight and ventilation to reach pitch level as possible. The arch itself is not just a cosmetic feature; it supports the north roof and a sizeable area of the south roof.
THE ARCH AND ROOF
The arch was designed to give the appearance of solidity without incurring the penalty of high wind loads. The arch has a lattice form consisting of 41 steel rings (diaphragms) connected by spiralling tubular chords and is formed of 13 modules with two tapering end sections. The arch (7.4m in diameter at the base and weighing 1,750t) tapers at its ends and is supported on 70t hinges which are in turn supported on concrete bases founded on piles 35m deep. Inclined from the vertical, the arch is held in position by a series of forestay and backstay cables tied to the main stadium structure. The leading edge of the north roof is in turn suspended from the arch by the forestay cables. Cables from the arch are arranged in a diagonal pattern to help spread loads to control in-plane bending while also providing out-of-plane restraint to resist buckling. The arch structure is 133m in height, with a span of 315m and is the longest single-span roof structure in the world.
The 50,000m2 roof is essential to the operation of the stadium as a sporting and concert venue. Weighing some 7,000t, the roof has a number of retractable edge sections which can be manoeuvred to allow direct sunlight to reach all parts of the grass pitch (to allow the pitch to achieve top quality). If necessary (e.g. during inclement weather), the roof can be retracted in around 15 minutes to cover every seat inside. The arch at a 68° tilt from the horizontal supports 5,000t of the roof structure. With its load-bearing capabilities, the arch allowed designers to eliminate the need for columns within the interior, which means that every stadium seat has an unobstructed view of the pitch.
The arch fulfils another function aside from supporting the majority of the roof. It also provides a ‘beacon’ for the stadium, illuminating the north-west London sky on match days. The designer’s vision for the arch was a tube of light that would hover over the stadium at night creating an iconic statement. To achieve this effect, 258 metal halide floodlights were mounted within the arch to illuminate the internal faces of the lattice and the structural rings that form its structure. Because the arch is lit from within, the outer faces remain dark and increase the dramatic effect by adding depth and contrast and giving the appearance that the light is trapped within the lattice structure. The arch also has an aircraft safety light at the top.
CONSTRUCTING AND RAISING THE ARCH
Construction of the arch began in 2003; it was fabricated on-site using steel modules fabricated by steel subcontractor Cleveland Bridge. Cleveland Bridge has since left the project over some serious contractual difficulties with the main contractor Multiplex. The arch was lifted in four key stages in June 2004 and temporarily supported on five restraining cables. Structural engineers from the Mott Stadium Consortium worked closely with Multiplex and the newly appointed steelwork subcontractor Hollandia to transfer the load, in excess of 1,300t, to the permanent cable net and eyebrow catenary cable. The final positioning of the arch to 112° was completed at the end of 2005, with the arch being rotated to take up the full roof load.
CONTRACTORS
The main contractor for the project was Multiplex of Australia.Project management (PM) was undertaken by Symonds who also carried out the PM for the Millennium Stadium in Cardiff. The Structural Engineers and Consultants included SVE Franklin and Andrews; Nathanial Lichfield and Partners; Steer Davies Gleeve and Mott Stadium Consortium (Connell Wagner, Mott MacDonald, SKM, Weidlinger, M-E Engineers). The original steel contractor was Cleveland Bridge but they were eventually replaced by Hollandia. The M&E contractor for the project was Emcor Drake & Scull and the building services engineering was carried out by Mott MacDonald. The original stadium demolition was carried out by Griffiths McGee. For the foundations of the new stadium the piling specialist was Stent and the concrete specialist was PC Harrington.
PITCH LAYING
On 19 June 2006 the laying of the new Wembley turf was completed. The laying process took a week and required more than 10,000m2 of turf to create the new playing surface. The turf arrived at the stadium in giant rolls measuring between 12m to 16m long and 1.2m wide, and was transported in 25 lorry loads. The fibre sand pitch is made up of an underlying web of heating and drainage pipes plus 22,161t of crushed stone, gravel, grit, sand and a blend of sand / soil and fibre. The grass used for the turf was selected from 250 different varieties with each square metre of turf containing 150,000 to 200,000 leaf blades. To maintain the world-class Wembley pitch the roof will be left fully open between events to allow the turf to be exposed to direct sunlight and ventilation. The sub air system installed under the pitch has ducts that are able to supply warm air to the the pitch to heat it and the same system can also be used to remove excess moisture from the pitch if required. Steve Welch is the Grounds Manager responsible for keeping the turf in excellent condition.
FEATURES OF THE STADIUM
To understand the size of the project, the stadium encloses 4 million m3 inside the walls and under the roof. The construction has required 90,000m3 of concrete, 23,000t of steel and 35 miles of heavy-duty power cable. Four thousand separate piles were used to form the foundations, the deepest of which was sunk to 35m. The stadium roof rises 52m above the pitch and the circumference of the building is 1km. The roof structure covers 11 acres, 4 acres of which are movable. The 90,000 seat capacity makes it the second largest stadium in Europe next to the Nou Camp stadium in Barcelona with a capacity of 98,000, but it will certainly be one of the largest stadia in the world to have a covering roof. The seating is much more steeply banked than previously so that no seat will have a restricted view. Minimum seat depth will be 80cm, with a minimum width of 50cm.
The stadium will have the facility to convert to an athletics venue by virtue of a removable steel and concrete platform which will rise 6m above the football pitch (the new pitch is 4m lower than in the old Wembley stadium). Installing the running track decreases the capacity of the stadium to 68,000. The front row at each end will now be between 8m to 13m from the touchline, compared with 40m in the old stadium. In addition there will be 310 wheelchair spaces with attendant companion spaces, and increased capacity for other physically impaired spectators. There will also be 400 media seats, 2,618 toilets and four main banqueting halls, the largest of which can accommodate 2,000 people. The stadium incorporates an external concourse surrounding it which is able to cater food and drink for 40,000 spectators at one time.
CONTROVERSY AND EVENTS DURING CONSTRUCTION
When the project first started it was delayed for two years over financial and political difficulties and eventually got underway in late 2002. The stadium was supposed to be completed by May 2006 for the FA Cup Final (but this was transferred to Cardiff) after consultation with Multiplex about when the stadium would be finished. Multiplex are now paying penalties for the late finishing of the contract although they have threatened to sue WNSL over changes in the design which they suggest were responsible for the project being late.
A few construction problems have been highlighted during theproject. The first was a problem between Multiplex and the steel contractor Cleveland Bridge. Cleveland Bridge walked off the job in 2004 shortly before the arch was raised because they did not believe they would be paid for materials and there were irrevocable difficulties between the two parties. The problems resulted in two high profile court cases where the two companies have sued each other for breach of contract (Multiplex sued for £45 million and Cleveland Bridge sued for £22.5 million to recover what it believed it was owed). As of June 2006 the courts had found in favour of Multiplex because of breach of contract, but Cleveland Bridge is appealing.
The second problem involved a temporary roof support rafter, which fell by over half a metre in March 2006. This resulted in the evacuation of 3,000 construction workers and delayed worked while inspections and reports were carried out. Theproject was started again shortly afterwards.
Later in March 2006 a third problem came to light. The sewers under the stadium had buckled due to ground movement. Remedial work was put into action for this and is currently nearing completion. The stadium is expected to be completed by late summer 2006 and hosting a full programme of events during 2007.
About Wembley Stadium
Wembley National Stadium Limited (WNSL) is the company that has redeveloped Wembley Stadium as the world’s leading sport and music venue. Offering up to 90,000 fans unrivalled views of the action in state-of-the-art facilities while generating an unbeatable atmosphere, Wembley Stadium is setting new standards for supporters and performers alike.
The aim of the project is to develop an iconic stadium for football and rugby league, which also has the capability to stage major international athletics events. If the project is successful, the stadium will be suitable for holding flagship events, make available a specified minimum number of seats to the general public, and be financially viable in its own right without the need for ongoing public subsidy. Any profits generated by the stadium will be used by the Football Association for the benefit of football. The project is scheduled for completion in early 2006 and is expected to cost £757 million, of which the public sector funders are providing £161 million.
The original public funding, a lottery grant of £120 million from Sport England (the largest it has ever given), was paid in full at the outset of the project and used principally to finance the acquisition of the existing Wembley stadium and business in 1999. Had the project not proceeded in 2001 after it failed to secure the commercial financing needed, Sport England would have been entitled to recover its grant but this would not necessarily have been straightforward.
Lottery funding was provided on the basis that the stadium would be capable of hosting major international athletics events. Concerns about the viability of the proposed design led to the removal of athletics from the plans for the stadium but provision for athletics has now been reinstated.
In April 2001 the Football Association approached the Department to request further public funding for the project, having been unable to secure the commercial financing needed. In September 2002, after a detailed review process, the Department concluded that the project was worthy of further support and committed £20 million of government funding. In reaching its decision on whether to provide additional public funds the Department, working closely with Sport England, took account of Mr Patrick Carter’s review of the project and also took assurance from work by the Office of Government Commerce and other external experts. The Department also considered the risks that the project will face as it moves forward and the mechanisms put in place to address the risk of, for example, the stadium taking longer or costing more than expected to build or the project’s viability being undermined by a shortfall in revenue.
In negotiating the contractual arrangements for the project, the public sector funders accepted that their interests would be largely subordinated to the senior bank since it was providing over half the funding for the project, compared with their 21 per cent. In the worst case, the bank would have first call on the project’s assets in the event of the project getting into serious financial difficulty. But for other circumstances, the public sector funders secured provisions which protect the public interest and which should be enforceable without compromising the viability of the project.
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