A question of sport

Looking like a tarantula crouching over its Eastlands site on the way to the M60, the project will regenerate one of the poorest, crime-ridden boroughs, bringing with it hotels, sports buildings and other commercial development.

But it is also, claims lead architect Dipesh Patel, the first stadium to be designed with a really fine attention to detail, treated like any other building rather than a utilitarian, unsophisticated shed. And that includes new Arup-developed features designed to improve sightlines, along with generous concourses, trademark masts and ramps, and a landscaped 'civic' space outside.

Spectator comfort and enjoyment - a humanist focus - is the priority, insists Patel.

The stadium came about through a series of competitions.Arup started by putting in a scheme for Manchester's bid for the 2000 Olympics in 1992, but the city lost out to Sydney, where Bligh Lobb Sports Architecture built to acclaim at Homebush Bay. The Arup Manchester Olympic scheme was to have been an 80,000-seater on the same site, but with a slightly different footprint.

Then, in 1995, Manchester made a bid to become the site for the National Stadium and Arup's design for it even featured a closing roof.

But again that fell through and Wembley was successful, although little has happened there since, save for the production of a series of rising cost estimates dwarfing Manchester's final bill (Wembley is projected at £760 million, seven times more expensiv than Manchester). Manchester was then awarded the Commonwealth Games for th Queen's Golden Jubilee year. Arup Associ ates duly resubmitted and won the projec from client Manchester City Council, with former Arup Associates boss James Burland involved in all three phases.

As Wembley has proved, designing a sta dium for dual use can be problematic, sinc football fans say they must be close to th action.That tends to rule out the continenta habit of putting the pitch inside the middl of a running track. Sometimes, as with th two main stadia for the forthcoming footbal World Cup - in Yokohama, Japan, and Seoul South Korea - a moat and fences distanc fans even more. But in Manchester the brie was slightly different. Rather than hav the capability of running both event simultaneously, here it would be athletics first, then football as the sole sporting use.

So Patel and his engineering colleagues set to work - Arup boasting that its company structure allows for engineering and architectural solutions to be better integrated than with separate firms.

The Commonwealth Games stadium was to originally have a capacity of 38,000 - now 41,000 after better-than-expected ticket sales for the Games. This would initially be a rough horseshoe shape in plan with an 'unfinished' northern end plugged by a temporary stand 'moulded' from scaffolding and seats.

The games run from 25 July to 4 August, so the plan is to dismantle the temporary seating directly afterwards and complete the stadium design for football use carefully beneath the cable-net structure inside a tight 10 months. Football fans will get closer to the pitch because the athletics track is taken out and sold on (like the temporary stand's seats, it is reusable, so fits with Arup's sustainable desires) and a football pitch is created by digging down 6m and adding a lower tier of seating around its curved, TV screen-shaped perimeter.

In so doing, Manchester City FC benefits from a 48,500-seater home for a 'peppercorn' rent while a portion of the gate receipts goes to the council. It looks a good deal: the council also gets Maine Road, Manchester City's 35,000-seater home for the past 79 years. Council leader and devout Manchester City fan Richard Leese says that Sale Rugby Club is likely to take Maine Road as its base rather than the usual custom - for it to be sold off for 'football-themed' housing.

Sport England contributed £77 million of the stadium's £101 million cost, with some going on preparatory works to the form mine site and more on a UK Sports Institu alongside, concentrating on squash, cycli and track and field.

The stadium has been designed as a lan mark, with the arrow-like masts supporti the roof a highly visible locator from mil around, just as floodlight pylons used serve as an orientation device for away fan It sits in 'Sportcity', which includes t institute, a tennis centre, and the Faulkne Browns-designed Velodrome.

Patel's background in urban design h contributed to the stadium's setting. 'I wan ed to make this a calm, restful environmen a nice civic space, ' he says.

This is because, his thinking goes, su spaces are respected by those who use them just as some prisons use colour therapy.An he believes that architects who aren't steep in stadium design, as was the case with Frei Otto with his first stadium in Munich, bring something new to the party.

A generous pedestrian plaza surrounds the stadium, calculated in terms of egress times, disaster scenarios and police control, using special Arup software. Lining it are a series of £500 plane trees Patel fought to retain in the budget, along with stretches of landscaped gardens by Gillespies hugging the stadium.

'This is the centrepiece in the regeneration of Eastlands and a 365 days a year place, ' Patel explains. It is also, he adds, as far away as possible from the American tradition of stadia set in a sea of parking.He wants people to come and take a stroll around the site, even on non-match days, while a large KSSdesigned club shop (Arup's own did not happen) will also contribute to the allimportant dwell times. 'We tried to make every part of it better as an experience.'

Spectators enter the stadium though new, larger-than-normal turnstiles, which, when Manchester City comes to the ground, will boast wireless ticketing. The turnstiles, modelled with curved edges after the design team looked at barriers on London's Underground, are at the ground floor level of the eight spiral ramp towers. These towers, containing plant and acting as the base for eight of the 12 masts, were also a feature on the other Arup Associates-designed stadium on which Pate worked - the 1995 Johannesburg Athletic stadium.And Lobb's Sydney scheme featured four similar but fatter towers.

The bowl is another elegant, carefully tested feature. No one - least of all th groundsman fretting over grass growth - wants the kind of stagnant air condition created by a fully enclosed bowl. So this on has large, hand-adjustable louvres at high and low levels, while daylight is maximised by transparent roof sections. Originally these were going to be glass, but in fact th polycarbonate replacement may be a bette solution, since the complicated geometries of the soaring, impressive roof may be better served by a more flexible material. It is also much cheaper, which was important when the 'value engineering' team moved in.Glass was also a casualty at the top of the spiral ramp towers, but again the replacement concrete lid was, if anything, better. At night these towers will be dramatically lit, as will the masts, the highest of which rises to 70m off the ground. Aviation lights at their tips were not necessary, however (they checked), and anyway, red lights would have been anathema to the club, since it is a colour more associated with the deadly main rivals from across town, Manchester United. So they will glow blue, although City's light blue is used only sparingly inside.

The stadium's ends are low to minimise the impact on the housing to the southern aspect and sensitive area of the Aston Canal Corridor to the north. The roof is an undulating, attractive form which concentrates most spectators in the best places for athletics. But one of the only disappointments with the aesthetic appeal of the stadium can be seen from the eastern approach, on an elevation just below the roof. Clearly visible is a sizeable section of plant for catering. It was to have been cloaked by a mesh grille, but the mesh is too large - the architects s this will be dealt with.

Inside the bowl again, sightlines a impressive. Patel is proud of the TV geom try and the way that any spectator can th see every other face in the crowd - importa for the collective experience, and an atmo phere-builder. The upper tier's rake is vertiginous maximum 34infinity, with a 27infinity ra below it and a 20infinity angle of parabolic se raking on the lower tier to come. Diggi down to that tier will expose the playe entrance and allow access from changi rooms already built in the 'basement' the west stand. C-values (the calculatio representing a spectator's field of vision above the fan in front) are also impressive, with a minimum c90 on the top tier, c75 on the mid and c75 on the lower.

The seats are the standard PEL manufactured design, which figures in about 90 per cent of new stadia. Despite talk of advances in seat design - some have foreseen seats with computer displays for action replays or to order refreshments - these are unlikely because of cost and, frankly, nuisance (delivery of refreshments being the difficult part).

Having said that, Arup is designing its own stadium seat, complete with armrests, but Patel feels that advances such as Bluetooth will supercede hi-tech seat wizardry.

Kneespace is excellent, with a tread measurement of 800mm - many, such as original parts of Old Trafford and Arsenal's Highbury are 670mm, though the HMSO Green Guide, published since Hillsborough, suggests 800 as a minimum. And, aiding sightlines, Arup has developed recessed treads around the vomitories into the stadium, meaning that handrails are 150mm lower. It is a neat solution, and 226 spaces for disabled access in football mode - in every price grade section of the ground rather than all lumped in one ghettoised area - is another impressive, democratic feature.

The concourse areas are also different from normal stadia. Arup Associates has designed large, clean, ceilinged areas which resemble an airport terminal rather than a stadium, with Arup Fire helping to devise a strategy to help the look. If a fire breaks out in a refreshment area off the concourse, two sets of shutters come down and 'make-up' air is brought in under a gap while smoke is taken away. The concourse is a zero-rated fire compartment so effectively 'outside' in fire terms, and having no need for sprinklers anywhere in the building also cuts down on the final cost.

Light is brought in from the bowl through glass blocks - a greenish reminder of the field of play. Currently it is illegal to drink alcohol with a view of the pitch, but if the law ever changes, this whole wall can be stripped away. Future-proofing, Arup calls it. There are no exposed services, as with other stadia, like Cardiff, for example.

It has its own generators for the lights, so there will be no blackouts, as happened famously in 1997 at West Ham's Boleyn Ground in Upton Park, when a betting syndicate made sure the game ended prematurely.

If the generators pack up in Manchester, it failsafes to the mains, without delay.

In athletics mode, a 60m straight warmup track in the belly of the stadium is an interim preparation for athletes who have already stretched outside on a full-size track alongside. The internal track is made of the same rubberised material by Mondo as with the full, 400m eight-lane version inside the main bowl. Fast times are in prospect.

Hospitality boxes on the east and west - another important revenue-generator of the modern sporting venue - are expressed a pods to keep the roof as a separate entity 'flowing' over the bowl; lounges are exten sive and a glazed restaurant lines th southern end of the stadium. Glazing in a VIP area has been lined with an anti-shatte bomb blast film, and already the security i high in the environs of the stadium, with regular patrols of mounted police. There ar warm-up rooms, dressing rooms, a hug expanse of space given over to catering, and even a jail for the thuggish few.

Expandability is tricky, but it is no impossible, necessitating a remodelling o the roof.And transport to the ground will b improved by a new Metrolink station, which should be in place by August 2003.

The design team looked at a wealth o other stadia to find out how others hav done things. Renzo Piano (and Arup's 60,000 seater, flying saucer-like Bari stadium in Italy, the San Siro, Jo'Burg, Maine Road Highbury, Old Trafford and Chelsea wer among them. For Manchester, they hav chosen a concrete bowl frame rather than steel.They made sure they have been close to Laing's build process through a traditiona construction management contract rathe than the design and build often used with stadia. And they've fought hard against th value engineers to retain elements they thought were important to achieving an effective, stylish, inexpensive stadium tha people will enjoy.And they have succeeded.

Structure The most striking element of the City of Manchester Stadium is the cable-net roof. It has only been achieved through a close collaboration between engineers and architects from the outset of the design. The roof is made up of two separate structural systems. The primary system is referred to as the cable-net and is made up of the 12 perimeter masts, high-strength backstay rods and spiral strand forestay and tension-ring cables. The secondary or roof plate structural system comprises box section rafters arranged radially at approximately 8m centres supporting rolled steel purlins which in turn support either standing seam or polycarbonate roof cladding. The primary system is independent of the roof plate structure and was constructed in phase 1, whereas the secondary structure will only be finalised with the construction of the north stand roof in phase 2.

Roof plate In its final football configuration, the roof plate will consist of 76 rafters supported at the rear of the bowl by integral v-struts resting on concrete columns. These allow sufficient headroom between the rear seating terraces and roof structure, as well as providing for transfer of horizontal thrust from the rafters. Towards the inside of the stadium, the rafters cantilever by up to 14m past the support of the cable-net forestays.

Cable-net structure Each rafter is supported by its own forestay cable varying in diameter from 35 to 50mm.

Adjacent forestays are grouped together in fans of five or seven cables and supported at their upper ends by the 12 cigar-shaped masts of maximum 1,500mm diameter. The form of the masts has been achieved by fabricating from cylindrical central thirds and conical ends. The mast heads are tied back to ground-anchor foundations by the backstay rods. This system alone would be sufficient to resist gravity forces such as self- weight and snow. However, wind uplift would tend to force the forestay cables into compression which, as cables, they are unable to resist. This has lead to the development of an innovative solution referred to as a 'grounded tension ring' to maintain tension in the cable-net under all conditions. All forestays are linked at their lower ends by a 'catenary' tension ring of four grouped 40 or 45mm diameter cables.

This ring is pretensioned by four corner ties anchored to the ground. This system allows a prestress to be introduced into the cable-net that ensures that all cables remain in tension for all possible applied loads.

In summary, the structural solution for the roof has produced a design that not only adds to the overall stadium architecture but is sufficiently cost-efficient to have survived several 'value-engineering' cycles unchanged.

It is a design which cannot be attributed solely to the engineer or the architect.

Staircases 2.20 0.

External walls and windows 62.49 4.

External doors 3.75 0.

Internal walls and partitions 50.56 3.

Internal doors 31.98 2.

Group element total 590.36 46.5 INTERNAL FINISHES Wall finishes 5.17 0.

Floor finishes 14.56 1.

Ceiling finishes 4.17 0.

Group element total 23.90 1.8 FIXTURES AND FITTINGS 92.66 7.

SERVICES Sanitary appliances 10.33 0.

Services equipment 6.93 0.

Water installations 6.04 0.

Space heating and 78.40 6.

air treatment Electrical services 139.32 10.

Lift and conveyor 10.27 0.

installations Protective installations 3.28 0.

Communications 0.04 0.

installations Builders work in connection 0.83 0.

Group element total 255.44 20.

PRELIMINARIES 123.98 9.

AND INSURANCE TOTAL 1,267.83 100.

Costs supplied by Paul Stanion, Davis Langdon & Everest CREDITS TENDER DATE Varies for trade contracts START ON SITE DATE October 1999 COMPLETION DATE March 2002 (phase 1) Aug 2003 (phase 2) CONTRACT DURATION 30 months GROSS INTERNAL FLOOR AREA 68,983m 2TOTAL FLOOR AREA 33,000m 2FORM OF CONTRACT AND/OR PROCUREMENT Construction management TOTAL COST £101,828,021 CLIENT Manchester City Council ARCHITECTS Arup Associates: Dipesh Patel - lead architect, Steve Clark, Lindsay Johnston, Luke Mcadam, Abi McGilivray, John Miles, Marcel Ridyard, Roland Reinardy, Caroline Sohie, Alexandra Stevens, Callum Stewart, Michael Tite, Eugene Uys, James Burland (left Arup Associates Dec 1999) QUANTITY SURVEYOR Davis Langdon & Everest STRUCTURAL ENGINEER Arup Associates + Arup SERVICES ENGINEER Arup MAIN CONTRACTOR Laing LANDSCAPE ARCHITEC Gillespies TURF SPECIALIST STRI WIND MODELLING RWDI SUBCONTRACTORS AND SUPPLIERS wall cladding Spanwall; roof cladding Brodericks (Lorus); adjustable louvr Levolux; architectural metalwork Dane patEngineering; sundry steelwork Lionweld Kennedy; seats PEL; floo lighting Philips; precast Buchan; atrium glazing Spacedeck; pod claddin AMS Roofing (Eternit); rain screen Keyclad; ironmongery Trapex ; joinery Cuerdan; metal door/roller shutter Amb Door, blockwork ABC; ceramic block Astra-Glaz (Forticrete); landscaping Hiller; carpets Miliken; vinyl & epoxy floors 4M; box glazing SG Aluminium; signage Rivermead; temporary seating Interserve; track McArdle

WEBLINKS Arup Associates www. arupassociates. com Arup www. arup. com Davis Langdon & Everest www. dle. co. uk Manchester City Council www. manchester. gov. uk Commonwealth Games www. commonwealthgames. com/default. asp Stadium link including 360infinity panaroma shots www. commonwealthgames. com/venues/cms