Highways Agency

The Project

This is a project for replacing the Wolvercote Viaduct on the A34 at Oxford.

The A34 is a strategic route between the Midlands and the south coast. The Wolvercote Viaduct carries the A34 dual two lane carriageway trunk road (Oxford Western Bypass) over the River Thames flood plain, the Oxford to Birmingham main line railway, the Oxford Canal and the A40 Oxford to Cheltenham road.

The existing viaduct was built in the early 1960's. Mainly because of water leaking through the deck joints, the viaduct has suffered extensive deterioration which requires significant maintenance to ensure it remains safe. This work would be difficult, expensive, and cause traffic congestion, and would also fail to improve the parts of the viaduct that no longer comply with current design standards. A Whole Life Costing Analysis concluded that it would offer better value for money to replace the viaduct.

We invited tenders in February 2006 and in July of that year Costain Limited, with designer Jacobs, were appointed under the Agency's Early Contractor Involvement initiative to progress the scheme through planning and construction.

We plan to replace the A34 Wolvercote Viaduct while ensuring that we minimize disruption to the traveling public and to manage the environmental impacts of the work. During construction a new viaduct will be built to the south-east - i.e. alongside the southbound carriageway - of the existing viaduct, slightly nearer to Lower Wolvercote and Oxford, which will enable traffic to continue using two lanes in each direction throughout the construction period. The deck of the new structure will be re-used in the new viaduct. Passenger trains using the main Oxford to Birmingham railway line would be unaffected by the works. Similarly traffic at peak times on the A40 would be unaffected.

Once built the new viaduct will be in the same position and the same height as the existing viaduct and will continue to have two lanes in each direction on a slightly wider structure.

What Happens Next

Since we commenced work in the Summer of 2008 all the foundations and piers for the temporary viaduct have been constructed.  The steel beams have been erected, the reinforced concrete deck has been constructed and the drainage, waterproofing, kerbs tarmac and barriers installed.

We have changed the layout of the A34 to allow Southbound traffic to switch over to the temporary viaduct.  The Northbound traffic has been switched to the old Southbound carriageway

The South approach embankments have been widened and a new maintenance  access road established

Southbound traffic was switched to the temporary viaduct during the night of Sunday 8^th March 2009

Northbound traffic was switched to the old Southbound carriageway during the night of Monday 9^th March, 2009

We are currently demolishing the old Northbound carriageway which crosses the Oxford to Birmingham Railway, A40 and the Oxford canal

We have commenced the foundations for the new Northbound carriageway and work will continue as previously described to construct the permanent Northbound viaduct which we intend to complete by December 2009

We will then demolish the old Southbound viaduct and construct new foundations and piers.  The deck of the offline viaduct will be slid onto these piers in one night shift.(June 2010)

The two decks will then be stitched together with project completion programmed for August 2010