Identified in the Christchurch Lifelines Study as a bridge vulnerable to damage in a major earthquake, the Ferrymead Bridge on the key arterial route connecting the suburbs of Redcliffs and Sumner to the rest of Christchurch has subsequently been under investigation by the Christchurch City Council to increase its traffic capacity and upgrade its earthquake resistance. A contract was let in 2010 to undertake these works. Surviving the September 2010 Darfield earthquake undamaged, the bridge

more »

... victim to the February 2011 Christchurch earthquake with extensive liquefaction and soil lateral spread occurring at the site, displacing the abutments and piers inwards towards the centre of the river. After extensive investigation into options for recovering the bridge, the decision was finally taken to replace the bridge with a new structure. This paper outlines the initial design to widen and seismically upgrade the original bridge, the damage sustained by the bridge from the Christchurch earthquake and measures instituted to stabilise the bridge as a result of that damage, and focuses particularly on the design now developed for the replacement structure. The significant issues involved in achieving earthquake resistance at a highly liquefiable site and in constructing in an environment of ongoing earthquake activity are discussed.