Structural Engineering for Avalanche Mitigation

2019 | Terrace, BC

Close to Terrace, in northwest BC, there is a stretch of highway near Mile 35 that is responsible for 80% of avalanche-related closures in the area. With this issue posing serious safety concerns for travellers, the Ministry of Transportation & Infrastructure (MoTI) decided to install five remote avalanche control system units to trigger avalanches. The devices will help reduce closure time on the highway since the previous approach of heli-bombing can only be done in good weather and during daylight hours. In addition, this system also dramatically improves safety since employees will no longer have to deploy explosives while flying in a helicopter.

To get each unit in position, they had to be installed on towers and foundations high up in the mountains. McElhanney’s structural engineers assisted by preparing a foundation design (including reinforced concrete and post-tensioned rock anchors) that minimized site work, which was critical given the steep and challenging terrain requiring materials to be brought in by helicopter. Also, McElhanney assisted with site selection by evaluating local bedrock conditions in the area and providing construction inspections and contractor support during construction.