CROSS RIVER Partnership has ditched the contract for London's Hungerford footbridge following a series of setbacks.
A new contract for the footbridge across the Thames is to be signed shortly.
The decision to ditch the existing contract between client Cross River Partnership and the Costain/Norwest Holst joint venture was made after cost overruns of almost £20M on the intial £21M contract.
The showcase project to build two cable-stayed footbridges either side of the railway bridge is now running a year late. It had been hoped to have one bridge open this year.
Design revisions to the scheme are also under way to cut costs. Lower specification paving, expected to replace granite with precast concrete, and lower specification lighting are under consideration.
Proposals in the existing design by architect Lifschutz Davidson, including link bridges to the south embankment near the Festival Hall and the Millennium Wheel, and detailed restoration work to existing structures, could face the axe.
The new contract was negotiated because the scope of the works had altered so dramatically from pre-tender stage that the design and construct contract awarded to Costain/ Norwest Holst could not stand.
Chief among the unforeseen difficulties were constraints placed by London Underground on piling near the Bakerloo line tunnel under the Thames and London Underground fears that piling could set off Second World War bombs which may lie in the river bed (NCE 14 September).
The project has also suffered a number of foundation failures, requiring repiling and a review of aspects of the temporary works design.
A sheet pile cofferdam failed two weeks ago near the Victoria Embankment side of the job.
Movement of up to 300mm of Larssen 6 sheet piles driven through silt into the London Clay occurred when the cofferdam failed at the toe. Repiling with longer piles was completed at the weekend.
The failed cofferdam had two levels of tie-rods and walings, rather than the three given to those in deeper water further towards the centre of the river.
Half the ten cofferdams on the site remain to be driven since piling began in March.
The new contract for £39.5M will be let to Costain/Norwest Holst under the Engineering Construction Contract form.
The option two target cost form allows for savings to both client and contractor if targets are reached and replaces the £21M ICE Design & Construct form previously let.
The new contract reduces the involvement of the client's current engineer WSP, whose role disappears under the ECC form.
Westminster City Council's current project director Gareth Hardwick takes over as project manager under the new contract. Westminster is the lead partner in the Cross River Partnership Consortium, whose backers include other local councils, the London Mayor, Railtrack and LU.
A number of WSP engineers will remain on the project to advise the project manager.
'WSP will continue to advise on technical matters and will be responsible for any design work they have done so far, ' said Hardwick.
Commenting on the new contract he said: 'We chose the new form because it gets us working together to solve problems for the mutual benefit of the client and contractor.'