Transportation Award of Excellence
Adapting Infrastructure in the Face of Extreme Weather Tetra Tech
B
Proactive planning The highway is both a gateway and lifeline to the north. PSPC’s foundational responsibility in managing this transportation corridor is establishing the most cost-effective way to continue supplying the needs of Alaska’s population. This involves significant proactive planning to reduce the risk of supply chain disruptions and the isolation of local communities. As such, Tetra Tech’s methodology calculated the societal cost of a failure of each asset in its existing condition, the societal benefit of added resiliency and the construction cost of that added resiliency. A washout of an under-capacity culvert, for example, carries a much higher monetized consequence of failure than simply the cost of the culvert itself, as it can result in a road closure for several days or weeks. If such an event were to occur, the impact on the movement of 36
CANADIAN CONSULTING ENGINEER
goods and services through the transportation corridor could be catastrophic, with the resulting detours increasing travel distances by more than 1,000 km. Developing a novel approach Tetra Tech derived the project solution by working backward from the final objective. The team devised a methodology whereby the costs and benefits of improving the resiliency of the highway assets could be determined in such a way that these improvements could compete equitably for funding with other potential improvements. The approach, a first-of-its-kind implementation relating to transportation corridors, combined monetized risk-and-reliability with a climate change vulnerability asset management program. The project was delivered by a team of 10 specialists within the fields of climate science, hydrotechnical engineering, geotechnical engineering, geographic information system (GIS) analysis, highway design and construction and asset management engineering. For the client, the outcome provided a credible and defendable means for justifying capital expenditure decision making. September/October 2022
PHOTOS COU RT E SY T ET R A T EC H
ritish Columbia’s Alaska Highway is the primary transportation corridor connecting the contiguous U.S. with Alaska. It is of high strategic importance, providing a critical link to the north. The 900-km corridor travels through several ecological regions, crosses five mountain summits and runs alongside portions of several major rivers. Public Services and Procurement Canada (PSPC) teamed with Tetra Tech to develop a multidisciplinary study to evaluate the vulnerability of corridor assets against the potential effects of climate change. The project required an innovative approach for compiling and assessing the variety of asset components (based on type, location and condition). And then that approach had to be interwoven with a multifaceted decision-making schema to define the level of an asset’s climate resiliency risk, quantify all of the risks and weight them against social and economic drivers. The study included the evaluation of 410 large culverts across 361 sites, 74 geotechnical hazards and the 24 bridges within the corridor.
