Ara Tūhono - Pūhoi To Warkworth
major motorway extension through complex geology
The Pūhoi to Warkworth motorway is an 18.5km extension of the four lane Northern Motorway. On a greenfield alignment, it presents plenty of geotechnical challenges – steep slopes, difficult terrain, rivers, and streams – as well as featuring significant flora, fauna and places that are special for mana whenua.
We were engaged to work with the design and construction joint venture Fletcher Construction – Acciona JV.
how did we optimise, earlier?
We efficiently resolved challenges being faced on site with major cut slopes. We enabled construction works to continue during the critical summer earthworks season.
Our services included detailed geological mapping, and interpretation, co-ordination of additional site investigations as well as undertaken significant slope stability analyses to ensure that every stage of the works met with the stringent requirements.
While we were at it, we were asked to optimise ground improvements at the Northern Tie-in – a tricky piece of work and designed a three-metre diameter pipe jack under the existing live State Highway embankment – contending with very low headroom of less than four metres. We didn’t move mountains, and we weren’t the main consultant – but we certainly optimised the Geotech.
expertise
location
Auckland
project team
We worked with Andy and his team through the past two earthwork seasons on a number of challenges -from stabilisation of large cut slopes in challenging ground. The solutions have been realistic, reasonable and constructable and a real ‘value add’ has been having some of our team regularly working out of Andy’s offices in true collaboration.
