The South-East coast road on the island of Tutuila is cut into the volcanic rock and experiences occasional rockfalls directly on the road. Working through a local contracting firm, Abseil Access was engaged to stabilise four bluffs (up to 60m high) above the road. Tonkin & Taylor NZ provided the design work and developed the solution, a passive drape of Geofabrics HR30 wire rope reinforced double twist mesh. Geofabrics manufactured custom extra-long lengths of mesh to fit each site.
The Total surface area of mesh was 10,000m2. Without tall cranes or helicopter support, the team had to manually raise the mesh rolls to the top of each site. The netting was secured with a top cable anchored at 2.5m intervals to 32mm anchor bars. The anchor lengths were driven 2.5m into volcanic rock, with a hole diameter of 80mm. The team worked in extreme tropical conditions and the project was completed over a 6-month period.
