Illecillewaet Four-Laning

The Illecillewaet Four-Laning Project improved safety and capacity on a 2.1km stretch of Highway 1, approximately 45km east of Revelstoke, BC. The site was characterized by steep terrain, crossing over an unstable slope up the mountainside from the CP Railway tracks. BASIS was engaged to perform value engineering to optimize the design of a 500m section, which had a large number of stabilization piles and tall retaining walls. Together with EAC and the Ministry, BASIS implemented an innovative redesign which met the objectives of providing a similar level of reliability while significantly improving constructability. The optimization resulted in savings of over $4 million in construction costs. 

A cantilever structure, or half-bridge, was used to span over a series of downslope gulleys to replace a tall, difficult to construct, piled retaining wall supporting the downslope road edge. The half-bridge allowed for the roadway alignment to be raised and shifted south in order to significantly reduce upslope walls. This significantly decreased costs , and improved the overall construction schedule. In total, the redesign included a 136m long steel girder half-bridge structure, 46 stabilization piles, and 240m of lock-block MSE walls.

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