Assignment
The new SH20-1 Manukau Extension motorway project serves as a key connector to relieve traffic around the city centre. The 5 km (3.1 mi) motorway forms the southern gateway to the Western Ring Route skirting Auckland and is designed to bypass the city between Manukau and the North Shore and to support growth at the Auckland International Airport business zone.

Our Role
Golder produced an alternative design that was determined to be more cost-effective to construct. We developed foundation designs for 12 permanent bridges, including an underpass, a flyover and two stream crossings, as well as a temporary bridge and the widening of a carriageway beneath an existing bridge.

Deep lift asphalt on cement-treated crushed rock is the pavement material and marks the first time this technology has been employed in New Zealand.