Effects of vertical irregularities and construction quality in seismic fragilities for reinforced concrete buildings

Seismic fragility of buildings is often developed without consideration of irregularities and material qualities that can underestimate the prevalent vulnerability. This study demonstrates effect of vertical irregularities (VIs) and construction/design quality (CQ) on seismic fragility curves of reinforced concrete (RC) frames. A six-story three-bay RC moment resisting frame designed for seismicity of Vancouver, BC, Canada, according to the 2005 National Building Coded of Canada, is considered. Three sets of 15 ground motions, corresponding to the 2%, 5%, 10% probability of exceedence in 50 years hazard level, are matched to Vancouver's mean response spectrum at the natural period of the structure and used for nonlinear time history analyses. Sensitivity of seismic demand (i.e., interstory drift and story shear) on VI and CQ is studied. Finally, the interaction effects of VI and CQ in seismic demand of a structure is considered.