Lochwinnoch Bridge Replacement

THE CHALLENGE

Lochwinnoch Bridge is a single span simply supported steel half through bridge carrying the B789 across the River Calder in Lochwinnoch with a clear span of approximately 16m. The bridge deck is substandard with the load carrying capacity restricted to 7.5 Tonnes, accompanied by traffic signal controlled single lane operation. In order to improve the transportation links through the town, Renfrewshire Council required advice on the strengthening or replacement of the bridge to carry full current highway loading requirements.

SYSTRA’S ROLE

SYSTRA was appointed to investigate possible options for replacing the existing bridge including assessing the suitability of re-using the existing masonry abutments. Extensive intrusive investigations of the abutments confirmed that they were of variable structural integrity and consequently a bored concrete pile solution through the existing abutment was adopted for the replacement bridge foundations.

The new deck comprising prestressed beams with an in-situ concrete infill will be cast integrally with the abutment pile caps. Parapets comprised precast concrete units clad with stone masonry.

SYSTRA also undertook the Supervisor role for the construction phase of the works in accordance with the NEC3 contract.