SH1 Waikato Expressway Tamahere and Cambridge Sections

The ‘Waikato Expressway Cambridge to Tamahere Section’ project provided an alternative State Highway 1 (SH1) alignment around Cambridge. The Waikato Expressway project is part of Waka Kotahi/ NZTA’s Roads of National Significance (RoNS).

The project involves the design and construction of approximately 16km of four-lane median divided State Highway, three interchanges and eight bridges including the 200m long Karapiro Gully Viaduct to the east of Cambridge.

Gaia Engineers was the Lead Geotechnical Designer of the project and designed 8 (Mechanically Stabilised Earth) MSE bridge abutment walls with steel ladder reinforcement, which support the bridge abutment without piles. The Karapiro Viaduct was founded on 40 driven steel tube piles up to 45m deep.  Earthworks comprised a total volume of 1.25 million m3 of cuts and fills. Ground improvements for the earthworks and bridge abutment foundations included soil nail stabilisations and high tensile geotextiles.

Construction commenced in late 2013 and official opening was in December 2015. Gaia Engineers provided continuous geotechnical services over 5 years from the tender in 2012, during the detailed design in 2013, during the construction phase from 2013 to 2015, and during the defects notification period until 2017.