Seismic fragility, loss, and resilience assessment of Canada's bridge infrastructure

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Both southwestern British Columbia (BC) and St. Lawrence Valley are at significant risk of a strong earthquake. Bridge structures in these regions are seismically vulnerable due to aging and deterioration, outdated design and deferred maintenance. For example, nearly 40% of BC highway bridges were built before the first probabilistic seismic hazard map has been developed [1]. Moreover, the transportation infrastructure in BC and Quebec consists of a diverse collection of bridges that vary in material, type, connectivity, geometry and design details. Given the complexity, existing research falls short of providing a comprehensive, consistent and reliable seismic assessment of the bridge inventories in West and East Canada. The proposed program aims to enhance the seismic resilience of Canada's transportation infrastructure. An integrated framework to assess the seismic fragility, loss and resilience of regional bridge systems in BC and Quebec will be developed to achieve this goal. First, high-resolution bridge inventory databases will be built by surveying a large number of drawing files from British Columbia Ministry of Transportation and Infrastructure (BCMoT) and Transports Quebec (MTQ), respectively. Second, high-fidelity response and capacity models will be developed in OpenSees (an open access software for seismic analysis) for various types of bridge components that incorporate nonlinear behaviours, design variations and different sources of uncertainties. Third, machine learning tools will be developed to group bridges with similar seismic performance, through which the bridge inventory will be sub-divided into several representative bridge systems (RBSs). Class fragilities and parameterized fragility models will be derived to represent the damage potential of grouped and individual bridges, respectively. Last, a web-based survey will be devised to quantify the relationships between component damage and expected seismic losses due to closure decisions and repair procedures. Response data from the survey will be utilized to perform seismic loss and resilience assessment for each RBS. The success of this program will bear a profound impact on the improvement of current design practices and provide bridge engineers with improved situational awareness on the seismic risk of Canada's bridge infrastructure. The proposed research will enable a more effective post-hazard emergency response and a faster restoration of network mobility. It will support planning, retrofit and risk mitigation decisions regarding the allocation of limited resources to maximize the seismic resilience of bridge networks. The developed frameworks and methodologies can be congruently applied to other structural systems when subjected to different types of natural hazards. The research will provide interdisciplinary training for HQP and an opportunity to teach a diverse student body about the role of science and engineering in improving the infrastructure resilience.