Assessment of seismic vulnerability of typical Quebec city bridges considering the site-specific amplification effects

摘要

In this paper, the seismic performance of 1970s regular R/C bridge is investigated in terms of ductility demand, considering site-specific time histories and the amplification effect of soil with heterogeneous stratigraphy. The five seismic site classes of the 2005 National Building Code of Canada were used in this study and seismic site analyses were performed on soil columns representing real stratigraphies of typical Quebec City soil profiles. A total of 24 linear modal dynamic analyses and 24 nonlinear time-history analyses were performed using historical earthquakes representative of Eastern Canada. It was found that the bridge model shows yielding at the base of the columns for site classes C, D, and E. For site classes D and E the 2005 NBCC amplification factors were found to underestimate the amplification effect on the bridge's response. These results also show that the energy dissipation is a better indicator of damages than the permanent displacement.