Upgrading of Three Historic Arch Bridges over the Orange River near Keimoes, South Africa

摘要

This project is located on the South African National Roads Agency SOC Ltd’s (SANRAL’s) RouternR27 near Keimoes in the Northern Cape Province of South Africa. The overall objective was tornimprove traffic capacity and safety of the route, with the main focus being the widening of fourrnsingle traffic lane bridges over the Orange River floodplain. This paper reviews the upgrading of thernthree main historic arch bridges.rnThe project included a detailed hydrological and hydraulic assessment which resulted in the raisingrnof two of the structures by approximately 2,5m to prevent overtopping of the structures duringrnlarger flood events. The largest of the three bridges, a ten span arch bridge, was at a higher level andrnthe existing deck was therefore retained and widened. The raising and/or widening of the bridgesrnhad to comply with heritage requirements as these structures, completed in the early 1930’s, havernsignificant historical importance. This resulted in the original form and appearance to be retained byrnusing a similar arch configuration and detailing. Construction was completed in 2013.