Stadium Bow Volume
Multiplex Constructions (UK) Ltd
Foster & Partners, HOK Sport
Connell Mott MacDonald, SKM Consulting
The new Wembley Stadium opened to the public on 9 March 2007. The all-seat stadium is owned by the Football Association (FA) and operated by its subsidiary Wembley National Stadium Ltd (WNSL). Construction of the new Wembley Stadium, which began in October 2002, was at times controversial. The aim of the project was to design and build a state-of-the-art national stadium, unlike any other in the world, which would be the home of English football and to host large events such as Cup Finals, music events and athletics.
The stadium, with a retractable roof and a 135m high arch, visible throughout London, stands as an association football venue in Wembley Park in London. With 90,000 seats it is the largest stadium to have every seat under cover.
The stadium is the homeground for international matches of the England national football team and the English domestic cup finals. The stadium hosted the FA Cup, Rugby League Challenge Cup, National Football League and FA Community Shield. The stadium also hosted the 2007 and 2008 Race of Champions. Apart from sporting events, the stadium also played host to music concerts of George Michael, Madonna, Coldplay, Mettalica,U2, Oasis and charity music shows including Concert for Diana and Live Earth.
The old Wembley Stadium
The old Wembley Stadium, with its much loved twin towers stood tall as a standing memory of British sporting history until it was closed in 2000, before being demolished in September 2002. The venue was originally developed as the main attraction of the 1924 British Empire Exhibition.
Construction work of old Wembley Stadium began in January 1922 and the stadium was inaugurated on 23 April 1923. Architects Sir John Simpson and Maxwell Ayerton designed the stadium, which had a capacity of 127,000.
FA Cup finals between 1923 and 2000 and League Cup finals between 1967 and 2000 along with seven European finals were held at the ground. The old Wembley stadium witnessed its home team winning the FIFA World Cup in 1966.
Wembley stadium 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 Populous (formerly known as HOK Sport).
The stadium is designed like a bowl and its 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 five-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 Wembley 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 that 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 left the project shortly after 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.
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 is 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.
Wembley Stadium features
To understand the size of the project, the stadium encloses four million cubic metres within the walls and under the roof. The construction 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, four 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.
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 and the seats have more legroom space. The seats are arranged in three tiers: lower 34,303, middle 16,532 and upper 39,165.
The stadium has the facility to be converted into an athletics venue by virtue of a removable steel and concrete platform which rises 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 is now between 8m to 13m from the touchline, compared with 40m in the old stadium.
In addition there are 310 wheelchair spaces with attendant companion spaces, and increased capacity for other physically impaired spectators. There are 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.
The stadium has 26 lifts, thirty sets of escalators and 164 turnstiles for the convenience of spectators. There are 34 bars, eight restaurants and 688 food and drink kiosks placed in and around the stadium. It also features 47 retail units including programmes, merchandise and betting. Seven cash machines are conveniently located around the stadium.
Finance of the new Wembley 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 £352m, with total project costs of £757m. The final stadium costs amounted to about £800m.
Under such an arrangement, the client is protected from exposure to budget over-runs or delays in construction. That risk was 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 £120m was made into the stadium. Financial backing of £426m for the project was secured through West Deutsche Landesbank of Germany. Ken Livingston and Brent Council secured £21m in funding for the project and a further £17.2m from WNSL for improvements to transport infrastructure in the area around the stadium.
The stadium is linked to Wembley Park Station (London Underground) via Olympic Way and also Wembley Central 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.
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. 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 it was 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.
Controversy and events during construction
When the project first started, it was delayed for two years due to financial and political difficulties before eventually getting 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 following consultation with Multiplex about when the stadium would be finished. Multiplex was unable to complete the stadium within the scheduled time and had to pay penalties. In December 2008, Multiplex sued the stadium designer Mott MacDonald for £253m saying that it was denied access to key design information that led to increased steelwork costs.
A few construction problems were highlighted during the project. 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 sued each other for breach of contract (Multiplex sued for £45m and Cleveland Bridge sued for £22.5m to recover what it believed it was owed). In September 2008, Multiplex won the case and received £6m from Cleveland.
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. The project began 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 started later on. The stadium was scheduled to be completed by late summer 2006, however, it was completed in March 2007 moving the scheduled sport events to other stadium.