RECENT DEVELOPMENTS IN BRIDGE CONSTRUCTION ON THE SOUTH AFRICAN NATIONAL ROADS NETWORK

With the increase of traffic volumes in the South African national roads network, especially in the entry to the economic development zones, commercial centers and local residential areas, quite a number of interchanges and overpass bridges had to be built in recent years. In the busiest sections of the national routes N1 and N12, three highway bridges were built without closing traffic during construction in the last four years. The costs reduced dramatically comparing with conventional construction methods. In the construction of John Vorster Drive Interchange, Olievenhoutbosch Interchange and Concorde East Overpass Bridge, the complete superstructures were precast above or alongside the expressways, then they were placed by vertical, horizontal and rotating movements to the final designed positions. This paper presents the new construction technologies applied in these bridges in detail.