Electronic Supplement

Existing buildings, particularly those predating modern building codes, pose significant seismic risk in regions of high seismicity worldwide. In the City of Vancouver, British Columbia, reinforced concrete shear wall (RCSW) buildings are prevalent in tall building construction. Many of these buildings were constructed prior to the introduction of ductility requirements in the Canadian concrete standard during the mid-1980s, and predominantly serve as residences for renters, seniors and low-income populations. This study quantifies the collapse risk of these tall non-ductile RCSW buildings to understand their seismic vulnerability. Leveraging a comprehensive database of pre-1980 RCSW buildings, a framework is proposed to generate representative archetypes using a random forest regression model. An automated workflow is developed to facilitate nonlinear structural analyses of these buildings, and a sample of 25 archetypes of varying heights, i.e., 10-30 stories, are selected to evaluate their seismic performance. The results indicate a high risk of collapse, ranging from 9%-29% in a 50-year period, significantly higher than the collapse risk target of 1% in a 50-year in ASCE 7. The results also indicate that collapse risk can be significantly underestimated when (1) taxonomy-level fragility functions are employed to characterize the performance of this unique typology of buildings, and (2) when the ground motion amplification effects of the Georgia sedimentary basin below Metro Vancouver are neglected.