Viaduct Solutions for Unstable Slopes in the Kicking Horse Canyon

This paper presents an innovative viaduct solution using accelerated bridge construction techniques crossing a series of unstable slopes, active landslides, and avalanche and rock fall paths along a treacherous highway section of the Kicking Horse Canyon Phase 4 project in British Columbia, Canada. The utilization of compact precast concrete components significantly minimized on-site labour requirements, improved the constructability, and reduced the construction schedule and cost. Approximately 1.8 km of viaduct structures were designed to span the unstable soils. Significant loads from avalanches and landslides were imposed on the viaducts. The piled foundations were designed to resist the loads as soil failed around the piles during a landslide, rather than fully stabilize the slopes. A unique “drift-link” detail connected the piles to the pier caps to accommodate thermal movement, as well as provide load-sharing between piles for lateral loads.