A71 Bailey Bridge

Over River Irvine, North Ayrshire

This contract was for the construction of a new bridge to replace the existing Bailey Bridge over the River Irvine in Irvine, Scotland.

The existing bridge, erected in 1971, was a 3-span Bailey bridge that was supported on the original substructure of a railway bridge, which carried the Irvine to Kilmarnock line. The Bailey Bridge carried the A71, a two lane single carriageway road over the River Irvine.

The new structure is a single span bridge comprising two inwardly inclined tubular steel arches braced together near the crown supporting a steel/concrete composite ladder deck via steel hangers. The arch foundations are reinforced concrete pile caps supported on large diameter bored piles. The pile caps at each arch support are tied laterally with a post-tensioned ground beam. The deck foundation consists of reinforced concrete bank seats supported on bored piled foundations.

The new bridge was opened 2 days ahead of schedule in April 2010.