New viaduct for A34 crossing

Steelwork erection for the first section of the new Wolvercote Viaduct on the A34 at Oxford has recently been completed.

The existing concrete viaduct, built in the 1960s has suffered extensive deterioration and is being replaced with a new steel composite structure. The viaduct carries traffic over the A40 Oxford to Cheltenham road, the Oxford to Birmingham railway and the Oxford Canal.

The new viaduct will sit in the same position as the existing structure and causing minimal traffic disruption on the busy A34 means the project team have come up with a novel approach.

A new temporary southbound bridge has now been erected by Costain and steelwork contractor Fairfield Mabey adjacent to the existing bridge. Once this structure is completed, southbound traffic will use it, while northbound traffic is switched to the old southbound bridge. This will allow the northbound bridge to be demolished and completely rebuilt. Once finished northbound traffic will be diverted on to the new structure, allowing the southbound bridge to be demolished.

New concrete piers for the southbound bridge will be constructed and then the entire 250m long temporary bridge deck will be jacked up and slide across on to the new southbound piers. “It’s a complex procedure,” said Darren Dobson, Costain Project Manager. “But it allows the A34 to have four lanes open during the majority of the works.”

The new viaduct is scheduled for completion mid-2010.