Saleyard Bridge – an improved approach to precasting steel-concrete composite bridge decks

Saleyard Bridge carries the A465 Heads of the Valleys Road over the River Clydach near Gilwern, Monouthshire. It comprises a 67m single span steel-concrete composite multi-girder superstructure made integral with the abutments. A full depth precast deck was chosen to tackle site constraints and improve constructability. The alternative precast panel connection detail developed used straight laps to overcome the problems that can arise from using typical U-bar loop type connections between precast deck panels. The successful use of the precast panels proved that a deck design with straight laps was a practical alternative. The ability to increase the multi-beam centres and avoid cantilever edge formwork created a more economical solution with savings estimated at £500,000. The paper examines the detailed design and construction planning needed to realise the savings and speed up construction as well as improving site safety. The lessons learnt are also applicable to the wider use of precast panels as an alternative to insitu concreting.