State Highway 58 Geotechnical Investigation

Located in the Wellington region, State Highway 58 was considered one of the most dangerous highways in New Zealand. Tasked with making the highway safer for road users, Waka Kotahi engaged our team to provide geotechnical related services for the project.

We compiled factual and interpretative geotechnical reports for consent. Working collaboratively with the design team, we undertook optioneering and preliminary and detailed design for the route, which included 4 bridge foundations, 12 retaining structures, and multiple large cuts. These cuts, required to widen and straighten the highway, presented a major hazard for necessary work. To mitigate the danger, we used an observation design approach, which could be efficiently modified during the construction process to accommodate exposed ground conditions. We also conducted site investigations at night under temporary traffic management and coordinated with Wellington Water to meet geo-hazard resilience expectations for a nearby critical water pipeline.

Waka Kotahi’s commitment to safety before, during, and after the project took State Highway 58 from a dangerous to desired Wellington roadway.