The largest cantilever roadway structure in B.C was completed in 2007 on the Trans-Canada Highway approximately 10 km east of Golden in the Kicking Horse Canyon. In September 2004, Emil Anderson Construction Inc. was awarded the $17 million contract to upgrade a section of Highway #1. The tender design included the construction of a pair of bridges crossing and returning over Kicking Horse River in order to facilitate the widening of a 2.1 km stretch of highway from two to four lanes. Klohn Crippen Berger was engaged by the contractor to develop a Value Engineering redesign for the project. The objective was to develop a more economical and constructible design within the extremely rugged and environmentally sensitive terrain of the Kicking Horse Canyon. The use of structural and geotechnical design innovations, along with highway alignment optimization, allowed the roadway to remain wholly on the south side of the river. A unique and simple design concept was used to cantilever a 155m long section of roadway off the south bank of the river. The major design aspects for the castin-place concrete structure included a 4.5m cantilever concrete deck over the Kicking Horse River, a counterweight concrete box structure containing compacted fill, a support retaining wall at the river edge founded on steel pipe piles drilled into bedrock, and scour protection using locally sourced rip-rap. The design of the cast-in-place walls made special provision for supporting the formwork for the cantilevered deck. Careful planning of the deck casting sequence, and design of a separately cast high-performance concrete overlay were incorporated to reduce cracking and associated risk of chloride contamination of the deck. By eliminating the need for the two new bridges, savings of $2.5 million were realized, as well as dramatic reductions in the environmental impact of the project. The major environmental benefits for the redesign were the elimination of bridge construction within the Kicking Horse River, and the prevention of the loss of 0.36 hectares of important riparian habitat on the north side of the river. The Kicking Horse Cantilever, with its simple design and clean aesthetics, provides an unobtrusive and attractive structure along the bank of the scenic Kicking Horse River.
