Country: New Zealand
Key Area: Transportation
Services: Bridge Engineering,Civil Engineering,Geotechnical Engineering,Transportation Infrastructure Design

This project involved 850m of State Highway reconstruction in an alpine environment.  The existing highway is a strategically important link, single lane over much of its length, running through a National Park. 

The site has extreme topography, suffers frequent rock falls, and is in one of the highest risk seismic areas in New Zealand.  The design solution provided a two-lane carriageway throughout, using innovative half-bridge designs and two overhead rock fall protection structures, one of which carries an existing waterfall over the road.  The project also included an extension to an existing bridge and selected cutting of rock.  A Value Engineering solution was developed with a strong focus on buildability, cost, risk, and fully integrating environmental and engineering factors throughout.  

The upgrade has enabled the strategically important domestic and tourist route to be maintained in a safe condition.  The stretch of road around Candy's Bend was previously closed for between 8 and 10 days a year because of rock falls and slips, forcing motorists to use the Lewis Pass route adding 100km onto the journey from Greymouth to Christchurch.