In 2000, Smithbridge Group (then operating as McConnell Smith) completed the NZ$22m acclaimed Otira Viaduct. The bridge was constructed along the fault line running centrally down the South Island, therefore required something of an engineering feat to ensure its stability in inevitable tectonic movement. The bridge was widely commended in New Zealand, and received the Caltex Construction Award in 2000. The bridge demonstrates Smithbridge’s unique abilities to work in technically difficult circumstances, unpredictable climatic conditions and environmentally sensitive areas.
The bridge is a 440 m long viaduct in 4 spans, the maximum of span of which is 134m. The deck was constructed as ‘balanced cantilevers’ in pours of 4m. All formwork and temporary works were designed and built ‘in-house’ by McConnell Smith. Each pier is founded on 4m diameter pile up to 30 m deep, and constructed within a secant pile ‘cofferdam’ of 4.8m diameter. Excavation for all piles were executed by a Numa Down-hole Hammer rig.