Strengthening, rehabilitation and widening of the existing arch bridge on national route 7 over the Olifants River, South Africa

Abstract

This paper describes the rehabilitation of the existing bridge over the Olifants River. The bridge is on National Route 7 near Klawer and dates back to 1957. The defining feature of this elegant bridge is a concrete arch spanning 92.7 m. The existing bridge displayed extensive cracking, failed expansion joints and spall damage to beam soffits. Some columns showed vertical cracks while some foundations presented with horizontal cracks. The arch presented with longitudinal cracks on both the upper and lower surfaces and a previous attempt to fill the cracks proved unsuccessful, as the cracks continued to widen. This paper presents the investigations undertaken to determine the cause for the observed defects as well as the methods employed to rehabilitate the bridge. These measures include strengthening with carbon fibre, coatings, patch repair, replacement of reinforcement, replacement of expansion joints and replacement of parapets. The work commenced early 2016 and was substantially completed mid-2018.