Contract NRA N014-057-2014/1F: For Consulting Engineering services for the rehabilitation of structures on National Route 14 Sections 5 to 7: Upington to Kuruman
The scope of Works included the rehabilitation of three bridges on National Route 14: two over the Olifantsloop river near Olifantshoek and one over the Ga-Magara river near Kathu.
The construction works for the Olifantsloop river bridges (B4835 and B4836) were almost identical. Due to exposed deck void formers and a lack of sufficient cover, reinforced concrete overlays were installed to strengthen the existing bridge decks. Due to the raised deck profiles, expansion joints were replaced, and the vertical road alignment of the bridge approaches were adjusted. Outdated parapets were demolished and reconstructed. Spalling repairs were performed and all exposed concrete surfaces were covered with a protective coating.
Due to dewatering of the dolomitic soil profile below bridge B5512 over the Ga-Magara river, partial settlement and rotation of the substructure occurred. The subsoil conditions were stabilised through pressure grouting, and the affected area was canalised with a concrete river-bed lining to prevent further ingress of water. The vertical road alignment was reinstated by the hydraulically jacking of two of the bridge decks to their original design level and the re-alignment of the eastern road approach.