Design and Construction of Next Generation of Arched Wildlife Overpass - Yoho National Park

Terry McGuire P Eng, McGuire Consulting
Topic Area
Terrestrial Wildlife and Ecosystem Interactions with Transportation

Twenty years after the first wildlife overpass on the Trans-Canada Highway in Banff National Park was constructed, the seventh wildlife overpass within Canada's national parks has been constructed. This arch structure, along with four wildlife highway underpass crossings over an eight kilometer stretch represent a continuation of the largest highway mitigation complex in the world as Parks Canada embarks on widening a further 48 kilometers of highway through Yoho National Park, Canada.

Building upon the success of environmental mitigations such as right-of-way fencing and 38 wildlife underpasses and 6 overpasses of varying geometries employed in Banff National Park (as presented at previous ICOETs by Dr. T Clevenger and myself), this next phase of highway expansion adds to and builds upon this experience and lessons learned.

Though adjacent to Banff National Park, Yoho National Park has slightly different ecosystems and geographical differences that must be reflected in constructing wildlife crossings. This presentation starts by highlighting the effect the highway currently has on the Park's ecology and how the desire to improve highway capacity creates the opportunity and motivation to construct greener transportation infrastructure addressing both wildlife-vehicle collision caused mortality as well as habitat and genetic connectivity.

Tight highway geometry in this next phase of four laning (twinning) requires that wildlife crossings span up to six lanes of highway without a structural mid-support. The resulting 33 m wildlife overpass arch continues Parks Canada's successful use of dramatic arch structures to provide economical wildlife passages over highways.

This project demonstrates that the arch concept can be used when longer clear spans are required due to site constraints. Its design and construction methodology may have wider spread application. Although not confirmed, a number of claims have been made that this is the longest precast arch span structure of this type in the world.

The presentation delves into several innovative design and construction techniques and challenges associated with the flat elliptical shape of the arch and its span along with the use of a slightly modified design-build tender procurement model.

In addition to this arch structure, four wildlife highway underpass crossings along with a number of other highway environmental mitigation measures that were employed in just eight-kilometers will be presented.

Finally, the presentation takes the opportunity to take a look ahead to other planned environmental mitigations as Parks Canada embarks on widening a further 40 kilometers of highway through Yoho National Park, Canada as public support continues for constructing extensive and expensive environmental mitigations in association with highway improvements in Canada's national parks.

Abstract Keywords
innovative arch overpass