2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
CONCEPTUAL DESIGN OF ROAD AND BRIDGE SUBSTRUCTURE IN NORTHERN CANADA WITH CONSIDERATIONS FOR CONSTRUCTABILITY AND CLIMATE CHANGE

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Author(s)
Ms. Michelle Liu, CPATT - University of Waterloo (Presenter)
Mr. Kurtis Hubert, University of Waterloo
Dr. Susan Tighe, CPATT - University of Waterloo
Abstract

Vehicular access to and from various communities in Northwest Territories rely on winter roads that traverse bodies of water subjected to deep freeze in winter months. Tlicho Winter Road connects the territorial capital Yellowknife and the community of Whati, a notable junction of various other winter roads that connect communities further north. Climate change has however caused a decrease in the reliability of many winter roads, leading to limitations in the movement of goods and natural resources. In light of challenges associated with winter roads, the Tlicho All-Season Road (TASR) was approved by First Nations and territorial governments in 2013. Stretching across the Wek?e?ezhi?? Land, the future TASR will provide year-round access to the community of Whati and will increase the days of service for connecting winter roads that are currently limited to the same service window as the Tlicho Winter Road.

The predetermined alignment of TASR inevitably traverses regions of discontinuous permafrost, an element that has posed problems to infrastructure in regions of high latitude and altitude around the world. When permafrost-rich soil is disturbed or thawed, the originally solid ground loses the bearing capacity required by the road or bridge structure above. This case study proposes three conceptual road design alternatives for a permafrost-rich section along the TASR, and a conceptual substructure design for the crossing at La Martre River where permafrost is also present. Thermosyphons, air convection embankment, and unilateral heat transfer pavement will be discussed. The surficial characteristics of various sections of the TASR are also examined.