Hybrid construction success at Coventry Arena

This Miller Partnership scheme is a flagship development for the client, Coventry North Regeneration, and will be a focal point for the redevelopment of the area. The unusual design of the arena incorporates a 32,000-capacity sports stadium, a 600Om^sup 2^ exhibition and concert facility and a 10,00Om^sup 2^ casino under the same roof. The whole is linked by a 'central street', glazed both ends, providing a visually striking and stimulating space that will dominate the Coventry landscape and will be clearly visible from the M6 motorway.

Hybrid construction

Situated in a former industrial zone, some four miles north of Coventry on the A444 road, the structure is due to be completed in August 2005, when it will be operated by the joint venture company Arena Coventry Ltd. Although the main structure is a steel frame, concrete plays a significant part in the design. For example, stadium seating decks are all constructed in precast reinforced concrete units. In addition, external walls incorporate split-faced concrete blockwork and horizontally emphasised curtain walling throughout.

The stadium is an asymmetric bowl with a full lower tier augmented by an upper tier to the West Stand. All main activities are contained within the West Stand, which - uniquely features a 70-bedroom hotel with its own reception/lobby, lift access, restaurant and all support facilities. On match days, hotel rooms can be converted for use as hospitality boxes. There is also a two-storey gymnasium and fitness centre in the south west corner. In addition, the West Stand accommodates 2500 hospitality guests with a 1000-seat conference facility at third-floor level.

The events and exhibition hall is a state-of-the-art facility that will meet the requirements of the most demanding exhibitor with total flexibility. For events, the multi-purpose space can accommodate 6000 people for rock concerts, indoor sports competitions, etc. The project also includes a casino constructed on several levels, with the main gaming floor situated below ground, beneath the exhibition hall.

Benefits of precast

Among the specialist concrete companies is Bell & Webster Concrete Ltd, a member of the Structural Precast Association (SPA), and Tarmac Topfloor, a member of the Precast Flooring Federation. While agreeing with the hand-in-hand approach, the SPA adds a rider that the construction industry has not yet entirely taken on board all the added benefits of precast in terms of programme savings and certainty, savings in preliminary costs, higher quality, and reduced risk - all leading to earlier completion. As long as the precaster is involved from day one, off-site works can be executed concurrently with the preceding main contract work, and frame elements will be ready for delivery and erection when needed.

Bell & Webster's contribution consists of supplying almost 6000 precast components for the complex, in the shape of 3442 terracing/balcony units, 2273 concrete steps, and more than 200 slabs and stair units. The terracing units offer one-hour fire resistance and are designed to withstand a load of 4.5-5kN/m^sup 2^. Units are available to a maximum length of 1 Im but are generally 7.5m long. This is the largest project of its kind so far undertaken by the company.

With an order from Laing O'Rourke in excess of 300,000, Tarmac Topfloor has supplied the stair package for the project with a total of 2200 risers and 130Om^sup 2^ of landings, equivalent to around 50Om^sup 3^ of concrete to the stadium, arena and some of the vomitory areas, which included plain flights, landings and scissor stairs. Working closely with the project's steel fabricator, William Hare Limited, the stairs needed to be carefully coordinated with the erection schedule of the main steel frame to help provide immediate safe access. Some of the staircases weighed almost 10 tonnes, which necessitated splitting the wider stairs into two sections to reduce the weight for crane handling. The precast flights were formed to incorporate baluster pockets and attached steel angle sections, which have been drilled and bolted to the main supporting steel beams for rigidity. All Topfloor's precast stairs are designed and manufactured to BS 8110(1) and can be produced to offer fire resistance of up to four hours.

Construction challenges

Bird & Marshall Ltd is the engineer for the stadium and its involvement in the project included value engineering at tender stage, design development and coordination, detailed design and documentation. The most significant challenges were the design of the 8500m^sup 2^ casino basement slab and the suspended exhibition hall slab of similar size to withstand high traffic loads. A mechanically-drained slab on ground replaced the original slab. This was a highly economical solution that replaced tension piles with pad footings. The post-tensioned in-situ concrete band beams and slab at exhibition hall level made it possible for the structural steel framing and roof to be erected before the floor plates were constructed.

Concluding remarks

Other recent projects on which Bird & Marshall Ltd has had a design role include Terminal 5 at Heathrow Airport, Dubai International Airport, CTRL St Paneras, Belgard Square in Ireland and Westminster Palace Gardens.

Client: Coventry North Generation

Main contractor: Laing O'Rourke

Architects: The Miller Partnership

Engineers: Bird & Marshall Ltd

Precasters: Bell & Webster Concrete Ltd Tarmac Topfloor