WEST MIDLANDS Passenger Transport Authority has criticised designers of a new bus station in Walsall for failing to spot structural weaknesses that are set to raise costs and have delayed its opening by three months.
Greater than anticipated sag in the £6.5M bus station's reinforced concrete roof has led to ponding of rainwater. Concerns have also been expressed over the impact resistance of steel piers supporting the roof slab.
The problems, identified last autumn, have pushed back the opening from December to the end of March at the earliest.
Architect Allford Hall Monaghan Morris and engineer Atelier One won the contract for design of the station in open competition in 1995. AHMM has been acting as contract manager. Main contractor is Shepherd Construction. The project is being funded by bus operator Centro, and through grants from Walsall City Challenge and the Government Capital Challenge.
Centro has now brought in an independent engineer to assess the structure and some remedial structural work has been carried out already. Further measures were being discussed this week between WMPTA, Centro and the architect.
A Centro spokesman said that due to legal and contractual sensitivity, no details about the contract or the planned design changes could be revealed.
The 2,500m2 lens shaped roof is a double curvature reinforced concrete slab, 325mm thick. Forces are contained by a 5m wide, 500mm thick perimeter ring beam. It is supported by 12 steel columns, each 300mm in diameter, and a new concourse building in the middle.
AHMM's original design was to cover the concrete slab with a 'green roof' of turf. Due to the ponding it is uncertain this will be instated, the Centro spokesman said.