Seismic vulnerability assessment of concrete shear wall buildings through fragility analysis

Seismic vulnerability assessment of shear wall buildings can be conducted through non-linear dynamic analysis, which requires detailed analytical modeling, the consideration of different earthquake intensity and structural performance measures. Reinforced concrete shear wall buildings were designed for Vancouver, representing a region of high seismicity in Canada, to assess seismic vulnerability of buildings constructed before and after the enactment of modern seismic design codes. The buildings either had a two-storey or a five-storey height, designed either using the 1965 or the 2010 National Building Code of Canada. Analytical models were generated for non-linear response time history analysis using computer software PRFORM-3D. Fiber-discretized sections were used for flexural response based on constitutive models for concrete and reinforcing steel. The nonlinear behavior in shear was modelled on the basis of sectional non-linear shear response. The shear wall models were validated against experimental data available in the literature before incremental dynamic analysis (IDA) was employed to generate fragility curves. Spectral acceleration at the fundamental period was used as seismic intensity parameter and inter-storey drift of the first floor was selected as the damage indicator. Performance limits considered include Immediate Occupancy, Life Safety and Collapse Prevention. The resulting fragility curves indicate that the life safety intent of the 2010 building designs has been met, while the same requirements could not be satisfied for the 1965 building designs.