SH25A Taparahi Slip Remediation
McConnell Dowell with joint venture partner Fulton Hogan and designers Beca and Tonkin+Taylor completed the new Taparahi Bridge and reopened State Highway 25A in record time.
The scope of work involved stabilising the slip and constructing a 124m-long by 15m-high bridge across the major slip.
NZ Transport Agency, the joint venture team and
the designers were committed to a process that was innovative and pragmatic, rapid and accurate. The three-span steel /composite bridge reconnecting Coromandel communities was completed in just seven months—under budget, with no lost time injury. It’s the quickest design / build bridge of its size delivered in New Zealand.
A project of this scale usually takes up to two years, particularly given the challenging wilderness location, variable geotechnical conditions and limited local contractor capacity.
how did we optimise, earlier?
We were engaged to provide all geotechnical temporary works required to stabilise the landslide zone and allow early mobilisation of heavy piling and crane equipment.
Key to success was our rapid interpretation of the ground and hydrogeological conditions,
which enabled a progressive ground model to be developed—allowing the team to work at speed. The site team began critical piling works within two weeks, continuing without any disruption.
Our early ground model was adopted by the permanent works designers for easy and cost- effective integration of the temporary works in to the permanent works. This saved substantial time and cost and reduced embodied carbon on the project.
The SH25A Taparahi project has won two awards to date
- Āpōpō Excellence Award for Innovation, May 2024
- ‘Bridge Project Team of the Year’ at the
New Civil Engineering Awards & Conference held in London in July 2024
I can categorically say, that without Andy O’Sullivan’s team leading the Temporary Works Geotech Design (which was later incorporated into the permanent works solution) we would never have achieved the results we did on the extraordinary project which was SH25A Taparahi Bridge.
