Design of Garrion Bridge, Scotland

Abstract

The construction of a 50 m span in situ reinforced concrete arch bridge in central Scotland was completed in the spring of 2002. This paper describes the background, design development and detailed design for this design-and-build scheme. The new Garrion Bridge was designed and constructed to cross the River Clyde 8 km upstream of the town of Hamilton and at the existing junction of the A71 and A72. The bridge forms part of a new junction arrangement to alleviate traffic congestion by forming one arm of a new gyratory system with the other arm utilising the existing three-span masonry arch bridge. Following preparation of various alternative bridge forms, the new arch bridge was designed and constructed in accordance with the outline design approved by The Royal Fine Art Commission for Scotland. The bridge was constructed utilising an in situ reinforced concrete construction over the river with the springing point supports founded on and stressed back to the mudstone/sandstone rock strata below the river. The paper describes the background to the scheme, geotechnical issues and the various alternative crossings developed during the tender period as well as describing detailed design issues.