NewsAurecon part of alliance to deliver strategic transport link in North Auckland

All projects in the New Zealand Upgrade Programme have targets to reduce construction emissions in order to meet the Waka Kotahi vision to have a low carbon, safe and healthy transport system.

This focus enabled the Alliance to unlock innovation throughout the tender development, Aurecon’s Transportation Industry Director Ian Sloane said:

“This is the first time Aurecon has delivered a project with a carbon budget and we assessed all options with an aspiration to arrive at the lowest embodied carbon solution as the highest priority. What this showed us was that choosing the lowest carbon design often also delivers better community, Iwi and cost outcomes. We will now be able to take these learnings to other major infrastructure projects we’re involved in.”

The Wēiti River Crossing was identified as the largest single contributor to O Mahurangi’s low embodied carbon solution, so during the tender phase, the Alliance refined the design which now delivers significant improvements from the original bridge, including:

• Reducing the number of piers in the Wēiti River, from three to two. This reduces the impact on the marine environment and allows clearer views and passage through the navigation channel.
• Construction methodologies have been improved, including a reduction in temporary works which help to minimise greenhouse gas emissions.
• A lowered entrance to the crossing will better fit with the landscape, enabling 235 metres to be trimmed off the overall crossing, reducing the amount of steel and concrete required.
• A cable supported crossing reduces the amount of concrete required, significantly reducing construction emissions. The northern pier has also been moved away from the coastal cliff to avoid excavation into the cliff face.

The Alliance’s desire to minimise environmental impacts drove other design solutions, including:

• Optimising the route for the new road to minimise the footprint of the project on the landscape, minimise earthworks and reduce the number of trees that needed to be removed
• An alternative intersection arrangement at Whangaparāoa Road that can be constructed with minimal impacts to road users and the community
• An alternative solution for a local road crossing that will take it underneath the Penlink road, reducing earthworks, and delivering a lower carbon, lower cost outcome

Innovation was also revealed through the Alliance’s digitally focussed approach. Aurecon developed an animated fly through of the project, and the Alliance intends to deliver the project in a completely paperless way, with all disciplines contributing to a single federated model, enhancing collaboration and providing accurate, real-time information to all stakeholders.

Aurecon will deliver the O Mahurangi project as part of an Alliance with Waka Kotahi NZ Transport Agency, Fulton Hogan, HEB and Tonkin + Taylor.

The name O Mahurangi was gifted to the project by Mana Whenua, in recognition of the ancestress Mahurangi, a tohunga (priestess) who lived in Hawaiiki and whose powers are said to have enabled the construction of the great voyaging waka Tainui.

When Tainui Waka arrived at what is now known as Wenderholm Regional Park in around 1,200, they gave the name Mahurangi to a small island adjacent to the Maungatauhoro headland. The islands' name gave rise to the harbour in which it sits, and eventually to the wider district and the Crown's land purchase.