Cover of Replacement of Browns Road Bridge
Replacement of Browns Road Bridge
  • Publication no: ABC-DES035-11
  • Published: 31 October 2011

Browns Road Bridge was identified by KiwiRail as requiring additional clearance to accommodate electrification. Opus’ challenge was to deliver concept, preliminary and detailed design within six months and develop an innovative solution that was buildable within a two week track rail blockade. Site constraints and other intricacies made the design process challenging and difficult. These constraints included a road alignment that was restricted by the proximity of intersections and consent requirements, and a rail alignment that was restricted due to the close proximity to Homai Train Station and pedestrian level crossings. A fully integral, reinforced concrete twin portal structure was designed. The spans are unequal and varying in length. The portal deck is 325mm deep. The structure was constructed with three precast cap beams, nine wall units and ten deck beams. Match casting and as-built surveys were undertaken throughout the construction process to ensure accurate fit on site. The implementation of innovation in design and construction throughout the project led to the successful construction of an intricate and unique replacement bridge.