Seismic fragility analysis of pre-1975 conventional concrete frame buildings in Canada

Abstract

Fragility analysis was conducted for reinforced concrete frame buildings in Canada designed based on the 1965 National Building Code of Canada as representative of pre-1975 era of seismic design practice. Two-, five-, and ten-storey buildings were designed for Vancouver and Ottawa, representing buildings in high and medium seismic regions. They were modelled for inelastic response time history analysis, with respective inelastic hysteretic models for flexure and shear. Software PERFORM-3D was used to conduct incremental dynamic analysis under incrementally increasing earthquake intensity. Probabilistic analysis of the results of incremental dynamic analysis led to the development of fragility functions, which can be used as seismic vulnerability assessment tools. The results are compared with those generated for frame buildings designed on the basis of the 2010 NBCC. The comparison indicates that the probabilities of exceeding performance levels are significantly higher for older buildings relative to recently built fully ductile and moderately ductile buildings, respectively.