SEISMIC VULNERABILITY OF REINFORCED CONCRETE BRIDGE COLUMNS IN CANADA

Bridges are essential lifeline infrastructures that must remain in service after strong seismic events. Recent design codes implement performance-based design methodologies which may call for increased seismic demands. However, most of the existing infrastructure in Canada was built prior to the enactment of modern seismic codes of the post-1980 era. Recent earthquakes revealed seismic vulnerability of bridge structures with a number of deficiencies in regards to low seismic design force levels, inadequate column confinement and lack of column shear capacity. The objective of this study is to assess the vulnerability of reinforced concrete bridge columns in Canada. Computer software DRAIN-RC, developed for nonlinear dynamic analysis of reinforced concrete structures, was used to determine the deformation demands of bridge columns under selected Eastern and Western Canadian ground motions. Deformation demands were subsequently compared with available research data in the literature on column deformation capacities to assess seismic vulnerabilities. Results exhibit different levels of performance for existing bridge columns in different regions of Canada, with bridges in western Canada showing higher vulnerabilities.