wembley

W E M B L E Y S TA D I U M

Megan Livingston

History 1825,Wembalea -The anglo-saxon settlement located in northwest London, is rst recorded. 13

1880s, Wembley Park Leisure Grounds1 -Area is now known as Wembley -Park contains football and cricket pitches, a running track, fountains and waterfalls, walkways and owerbeds.

1889-1907, Watkin’s Folly1 -Sir Edward Watkin, Chairman of the Metropolitan Railway, proposes a tower, 350m (1,150 ft) high with in the Leisure Grounds. Tower is to serve as monument marking the railway line that will link central London. -Funding for Watkin’s Tower runs out and tower is abandoned at only 61m (200 ft) high. -In 1907, the tower is known as Watkin’s Folly is demolished.

1918, Great War ends1 -Government begins planning a British Empire Exhibition. -Centerpiece of the Exhibition is the Empire Stadium designed by architects Sir John Simpson and Maxwell Averton, and the e ngineer Sir Owen Williams. -The stadium with it’s trademark Twin Towers is constructed in the location of -Watkin’s Tower in 300 days at the cost of 750,000 pounds

1923, White Horse Cup1 -First event in the stadium

1924, British Empire Exhibition1 -Exhibition covers 219 acres including fountains, lakes, gardens and many pavilions, each representing the architectural style of the countries exhibiting. -Immediate success of Exhibition in April prompts its re-opening between May and October the following year -Empire stadium is preserved from intended demolition by Sir James Stevenson.

1923-2000, Empire/Wembley Stadium1 -Empire stadium is England’s National Stadium -The Empire stadium closes for redevelopment in 2000

Design Team The World Stadium Team (WST) is responsible for the design of the whole stadium including the Arch. A unique partnership between HOK Sport and Foster & Partners, the WST was formed in 1998 specically for this project. WST brings together a wealth of architectural experience, with specic expertise in stadium design. Its skills and knowledge will ensure that the new Wembley National Stadium and its major features such as the Arch are at the cutting edge of stadium design.1

Multiplex is the lead design and construction company on the new Wembley Stadium project. Founded in Australia in 1962, Multiplex is Australia’s largest commercial and residential construction company and a major property developer. It delivered Stadium Australia for the Sydney 2000 Olympic Games and has signicant interests in New Zealand, South East Asia and the Middle East. Multiplex is also ranked as one of the UK’s major construction businesses and is currently involved in a number of residential developments in London including The Knightsbridge and West India Quay; one of the tallest residential blocks in the UK and the 500m White City retail development1

The Mott Stadium Consortium is a gathering of world-renowned consulting civil and structural engineers, pooling a wealth of  experience in the design of major stadia. The Consortium comprises Mott Macdonald Ltd, Sinclair Knight, Merz (Europe) Ltd and Connell Wagner. Their combined experience includes work on over 30 stadiums within the UK, as well as Stadium Australia in Sydney. Their role at Wembley is to provide the overall arch scheme and member design.1 Connell Mott MacDonald is a global building design alliance between Mott MacDonald and its Australasian associate Connell Wagner. It provides multi-disciplinary skills and experience from over 800 building professionals, who operate from a network of ofces spanning more than 50 countries worldwide. Connell Mott MacDonald has been instrumental in the mechanical and structural development of the Arch.1

Design Wembley Stadium is the site of the English National Stadium.

The design of the new stadium builds upon the heritage of the old to provide future generations of sports and music fans with a venue equipped for the twenty-rst century. At almost four times the height of the original, covering twice the area, and with 90,000 seats, the new Wembley Stadium will be the largest allcovered football stadium in the world. 7

The new stadium allows the UK to bid for the greatest events in world sports from the World Athletics Championship and the Olympic Games

Features

partly retractable roof . When retracted it will ensure that the turf gets sufcient daylight and ventilation to maintain a perfect playing surface, while in poor weather it can be closed within fteen minutes to cover all seats.1

arch The roof is supported by a spectacular 133-metre-high arch that soars over the stadium, providing an iconic replacement for the old buildings landmark twin towers. Dramatically illuminated at night, the arch will be visible from vantage points across London.1

Stadium Facilities Beneath this arch, stadium facilities are designed to maximize spectator comfort and enjoyment. The geometry of the seating bowl ensures that everyone has an unobstructed view from each of its three tiers; seats are wider than in the old stadium, with more leg-room; the upper tiers are accessed via escalators; and a new concourse with ve levels of atriums, walkways, cafes, bars, shops, and restaurants wraps around the building allowing easy circulation and providing catering to 40,000 spectators at any one time. To create an intimate atmosphere during football and rugby games, the stadium has been designed with seats close to the pitch, yet it also has the potential to host track and eld competitions, for which a running track and athletics arena can be installed when needed above the pitch on a rigid platform covering part of the lower tier.1

Concept

The design of the new stadium is both functionally and architecturally signicant. Sir Norman Foster was responsible for the design of the arch and the roof structure.

First design shown to public Expression with four mass could have many other stadia around world Sun is full on pitch, virtually no shadows -Four mast on north create a triumphant approach from Wembley way. -South is left clear as it is tightly restrained by railway and also to maximize sunlight

Built Design Arch doing all things has to do interms of holding up the roof from cables more efciently more elegantly but vitally giving an image unique and special to Wembley

Triumphant-InvitingGateway-PermanentEmblematic Symbol

Glistening at Night on the skyline-a jewel- a tiara

“I can’t think of any project that so touches the popular universal cord. In that sense Wembley is a national monument, an institution that goes across the whole spectrum of society not just here(london) but beyond the shores”- Lord Foster

Structure Lattice Arch

Roof is supported by the lattice arch with an asymmetric catenary cable net and stayed trusses spanning 220m across the stadium bowl. A circumferential double compression ring or PPT around the upper terrace anchors the supporting cables and transmits horizontal loads around to tripod shear legs.3 Stayed Trusses

Underside of retractable roof in closed position. Truss depth increases towards support

Asymmetric Catenary Cable Net Unobstructed Stadium Seating

Prismatic Perimeter Truss Pitch

Concourse

Retractable Roof Panels

Constructing the Arch 1

Arch consists of 41 steel rings (diaphragms) fabricated in North East England and delivered to the Wembley Stadium site in thirds.1

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The Arch was fabricated on site in 2003 over a period of ten months. The lattice form was designed to give the appearance of solidity without incurring the penalty of high wind loads.1 504 tubular “straws” cut to length on site form part of the structure1

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Three assembled diaphragms or rings were positioned and aligned vertically within the on-site fabrication sheds.1

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Each module was then lifted out of the retractable fabrication sheds and placed on stillages on the southern side of the stadium.1

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The diaphragms were connected together to form one Arch module 20.5 m long.1

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In total, 13 modules were assembled and welded together on site.1

A ‘Pencil end’ (or tapered end) was then welded to each end of  The pencil end sections were in turn attached the Arch structure.1 to giant 70-ton hinges, embedded in concrete

Raising the Arch

Arch was raised incrementally in four stages. The whole operation was computer controlled to ensure that the Arch is lifted evenly at all times.1

The Arch is slowly raised to an angle of approximately 30 degrees by ve sets of strand  jacks operating on ve gigantic turning struts taht are in turn attached by steel(pulling cables) to the arch. During this stage cables for the permanent roof support are attached.1

Fast Facts: -peak height of arch 133m (400ft) -4x hieght of original Twin Towers -illuminated the arch is visible from Canary wharf, 13 miles away

-spans 315m (824ft) world’s longest single-span roof 

The Arch will then be rotated steadily to 65 degrees, at which point the temporary restraining cables opposite to the pulling cables will take part of the load and control the postition of the arch.1

-arch alone weighs 1,750t; equivalent to 10 jumbo jets

-supports 5,000t, 60% of the overall roof weight

-arch eliminates the need for columns within the interior

-every stadium seat has an

The distinctive Wembley Arch is slowly rotated through the vertical position to 100 degrees, at which point the three main turning struts are lowered to the ground.

Once parked at 112 degrees, and all jacking operations have been completed, the last 2 turning struts are lowered to the ground.

In its nal position, the Arch At this time, restraint cables have is inclined to the vertical and held in place by 5 restraint taken the load and the pulling cables/turning struts are of little cables until the roof perimeter truss is completed and the use.1 permanent backstay cables can be connected. The Arch will remain at this position until the roof is erected and connected.1

Raising the Roof  FAST FACTS: -Roof weighs 7,000t -50,000m2

With the arch in position, the prismatic perimeter truss (PPT;circumferential double compression ring) is constructed around the upper terrace of the stadium seating structure. The PPT anchors the supporting cables and transmits horizontal loads around to tripod shear legs.6

-six roof components: the north roof, south roof, retractable south roof, four main north-south trusses, the prismatic perimeter truss (PPT) and the arch.

The north and south steel roof  structures are then built off  the PPT and supported off  of temporary towers. These roof canopies are made up of tubular steel truss rafters where the bottom boom is a stressed cable.6

-A cablenet with 16 backstays and 16 forestays connects the arch with the north roof, which in turn supports the north-south trusses and part of the south roof. -The roof structure covers 11 acres, 4 acres of which are movable on East, South and West edges. -retractable roof allows sun to reach all parts of the pitch -roof can be closed in 15 mins to cover all seating -largest covered stadium in the world

The temporary towers are removed as the roof is tied to the arch is held in position by a series of forestay and backstay cables. 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.6 When all 20 roof sections are installed aluminium sheeting is rolled onto the roof and rack and pinion sliding roof machinery are tted. 6

Construction Challenges No stadium has ever been built this way, so architects and engineers had to use complex computer models to predict how the structure would behave if built in certain ways.Given the special history of the previous Wembley Stadium, the designers had to pay particular attention to the atmosphere of the stadium, including the way it will sound with a full crowd cheering.Computers were used to simulate the acoustics of the new stadium before the design was agreed upon. 2

Fast Facts -215,000t of concrete -31,000t of steel -35 miles of heavyduty power cable.

March 2006 -Pipes running beneath the stadium buckled due to ground settling. When the pipes were laid, they appear to have not been supported properly underneath, especially where they join” It took months to dig up the pipes and make repairs. -3,500 workers were sent home for the day on full pay after a temporary roof  support rafter fell by over half a meter, costing the construction company an estimated 500,000. 9 Febuary 2007 -The retractable roof designed to open/close within 15 minutes has been restricted to operation during non-occupancy at a reduced speed(0.03m/s) slowing the process to 56 min and 30 seconds. The restrictions are due to concerns about the ablilty of the main northsouth trusses to cope with dynamic loading generated if the roof suddenly stopped while travelling at its design speed (0.11m/s). Spokesmen for Multiplex have stated the that “technically the roof can close within 15 minutes” however they will not disclose why engineers have required the reduced speed.

Construction Challenges Elements of Stadium Design

Spans with memory The way in which a long-span structure is constructed affects the stress distribution in the structure throughout its life. Long-span structures are fabricated from elements that are small enough to be transportable. They are then assembled in to sections suitable for the available cranage. While the sections are joined these elements are temporarily supported in a different way from their support in the completed structure. The structure retains a ‘memory’ of the different stress patterns experienced when supporting these varying loads.15

Deection In long span structures deformation can be many times the cross sectional dimensions of the elements. In contrast, the deformation in short span structures is so minimal it is standard practice to assume no deection in analysis. The longspan roof of Wembley Stadium deects by meters rather than millimeters.15 “It’s not that we’ve got hundreds of pieces to erect, it’s a case of going through a very denite sequence to make sure all the deections are as predicted.” -Petaccia, construction supervisor

Wind load The large area of stadia roofs makes wind loads are particularly signicant in their design. The wind uplift can often exceed the self weight, leading to net uplift and a complete reversal of  the direction of the forces in the structure. Even when there is no net uplife due to wind, for primary structures formed of arches or catenaries which perform best under uniform loads a critical design case can result from asymmetric wind pressures which lessen the downward loads more on one side of the span. Traditional design for windloads is based on average pressure readings over time with a gust factor adjustment. This method is appropriate for the many cases in which, vibrations are limited in magnitude, resulting in increased loads and occupant comfort issues only. Wembley Stadium additionally takes into account wind loads that result in excessive vibrations and have a potential for structural failure. Structural component analysis was based on a series of wind tunnel tests for the worst case loading in a full range of wind directions that accounted for the variable roof geometry.16

Quirks

Wembley Stadium has a 50 year design life

Wembley Postage Stamps

The unique shape of the bowl has been designed two-fold to amplify Wembley roar as well as reduce sound pollution by “swallowing” it. Light pollution is also treated with care. “Floodlights and other lighting have been designed to keep what stars can be seen above London shining.” 13

Color has been deliberately spurned the idea here is for the events and crowds themselves to add all the light, life and colour needed to bring this stately, steely-grey building to hugely animated life. Inside and outside, walls and ceilings have been designed so that banners, ags and pennants can hang from them. By night, the stadium will light up - a sporting coat of many colours - with the illuminated arch visible from many miles. 13

Quirks Just four days after the deal was signed, a 130 tonne Liebherr 974 demolition machine, dubbed ‘Goliath’, began tearing down the stadium’s historic twin towers that have greeted soccer fans from all over the world since 1923. ‘Goliath’ is the biggest machine of its kind in the UK. It was specically designed for McGee’s with the sole purpose of demolishing Wembley Stadium. 8 Stone from the twin towers will be turned into commemorative keyrings and sold at the new stadium when it opens in 2006. 8 Some of the crushed material was re-used in the concrete foundations of the new stadium. “The ghost of the twin towers”9 xed to remain within.

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.14

Bibliography

for the insatiable

1.) 2005 Wembley National Stadium Limited. 2 May 2007.   2.) “Wembley Stadium Case Study.” 2003 London Colleges. 2 May 2007.   3.) Sports Venue Technology. 2007 SPG Media Group. 2 May 2007. < http://www.sportsvenue-technology.com/>  4.) M-uthman. “Fun and Stuff.” 2007 Blogspot. 2 May 2007. < http://www.m-uthman.blogspot.com/>  5.) Ichniowski, Tom “315-Meter-Span Roof Arch Pivoted into Place in London.” Engineering News-Record. 21 June 2004 McGraw Hill Construction. 2 May 2007. < http://enr.construction.com/news/buildings/ archives/040621b-2.asp/>  6.) New Civil Engineer. 15 December 2005 EMAP. 2 May 2007.   7.)“Wembley Stadium.” Foster and Partners. 2 May 2007.   8.) Sweeney, Claire “Goliath, crushes Wembley icon.” 8 October 2002 Infolink. 2 May 2007 < http://www.infolink.com.au/articles/35/0C011635.aspx/>  9.)13 Febuary 2006 BBC. 2 May 2007   10.) August 2006 Multiplex. 2 May 2007   11.) Gonchar, Stephan “Stadium Roofs Offer Much More than Shelter.” Architectural Record. June 2006. McGraw-HIll Construction. 2 May 2007. < http://archrecord.construction.com/resources/conteduc/ archives/0606edit-1.asp/>  12.)“Wembley Stadium 1924.” 25 April 2007 Wikipedia. 2 May 2007. < http://en.wikipedia.org/wiki/Wembley_Stadium_%281924%29/>  13.)“We think its all over. . .” 9 March 2007 The Gaurdian. 2 May 2007. < http://arts.guardian.co.uk/art/architecture/story/0,,2030111,00.html/>  14.)“Delivering a New Wembley” Brent. 2 May 2007.   15.) Morely, Stephen “Stadia: Structural Giants.” INGENIA. 2 May 2007. < http://www.raeng.org.uk/news/publications/ingenia/issue22/Morley.pdf/>  16.) “Wind Effect Studies-A Critical Feature in Modern Stadium Design” January 2003 BMT Fluid Mechanics. 2 May 2007. < http://media.bmt.org/bmt_media/resources/42/Jan2003stadianewsletter.pdf/>