SH18 Hobsonville Deviation & SH16 Brigham Creek Extension

The SH18 Hobsonville Deviation and SH16 Brigham Creek Extension project is part of the Upper Harbour Motorway and Western Ring Route in Auckland. The project comprised four interchanges, seven bridges and 1.2M m3 of earthworks.

Gaia Engineers was responsible for the geotechnical design of 6km length of earthworks including slope stability analyses, settlement assessments and ground improvement design. SH16/SH18 project comprised up to 16m high embankments and 12m deep cuts in Puketoka Formation soils.

Construction commenced in October 2008 and was completed in August 2011. Gaia Engineers provided continuous geotechnical services from the tender in 2007, during the detailed design in 2008 and during the construction phase from 2008 to 2011.