GSI’s design-build model allowed for a rapid response and project flexibility. We collaborated with the client’s representative (Stantec) and CHBDC on the design, with a solution that reused drilling spoil on-site to reduce costs and environmental impact.

The project faced challenges due to the active landslide, a deep shear surface, and the need to maintain public access during construction on a steep slope. The solution involved a series of 3m deep counterfort drains to manage groundwater. 126 DSM 800mm diameter and 8m deep columns were arranged in a triple-row shear key to intercept the failure plane. The pavement was reconstructed, and we upgraded the stormwater infrastructure, including a new concrete swale drain.

The project was completed on time and within budget, with no incidents. The DSM method proved to be a highly effective and suitable solution, stabilising the critical road section and restoring resilience to one of Central Hawke’s Bay’s most important routes. As construction progressed and conditions dictated, GSI also managed to reduce the scope and further optimise the scope of DSM works and providing the client significant cost savings.