Cyclone Gabrielle: a collaborative approach to reconnecting communities

Recent experience in the aftermath of Cyclone Gabrielle on the East Coast of New Zealand highlighted the importance of collaboration during the immediate response to natural disasters. The cyclone resulted in extensive damage to the State Highway network, leading to multiple, extended closures of key regional connections. Given the large-scale recovery, close collaboration between New Zealand Transport Agency Waka Kotahi (NZTA), Higgins Ltd and Beca Ltd, allowed for swift community reconnection. As part of this project, innovative standardised buttress remedial solutions were developed that could be implemented at underslip sites to rapidly reinstate and support the road network. Slope failure causes varied across the network and included river toe scour, concentrated stormwater, soil saturation and stormwater infrastructure failure. Each of these causes needed to be considered in the formulation and application of these standardised buttress solutions to each specific site. On-site geotechnical professionals worked closely alongside contractors to communicate design intent, continuously made site specific adjustments, and provided feedback to the design team on constructability issues allowing the standardised buttress solutions to be rapidly updated for wide use on the network. These geotechnical professionals were able to assess the implementation of these standardised buttress remedial solutions, making sure they have addressed the root cause of failure. The collaboration between NZTA, Higgins, and Beca in developing these standardised buttress solutions demonstrated increased efficiencies and better outcomes for the community.