UBC Theses and Dissertations
Evaluating the functional recovery performance of a 1970s non-ductile reinforced concrete shear wall building Si, Jennifer
As seismic design in Canada continues to evolve, many buildings designed to previous building code editions are left to their own devices, creating a vulnerability in communities exposed to large earthquakes. This thesis will examine the preparedness of communities in the lower mainland of British Columbia in the event of a M9 megathrust earthquake. It originates from the Cascadia Subduction Zone, a seismic source off the west coast of Canada and the United States. The focus of this thesis will be on the seismic performance of tall, pre-1980s, reinforced concrete shear wall buildings, which represent a large proportion of Vancouver’s tall buildings. A nonlinear dynamic analysis of an archetype building fitting the mentioned criteria was carried out using shell elements in LS-Dyna. Furthermore, using the FEMA P-2018 rating system, a rapid screening tool that assigns a rating to indicate relative collapse risk for each building considered, a general picture of the risk these building pose to the community could be formed. In recognition that collapse safety is not enough to create a more resilient community, as part of this study, a recently developed framework called TREADS (Tool for Recovery Estimation and Downtime Simulation) is used to describe the performance of the building by following resilience-based performance measures. Results for the nonlinear assessment showed that the archetype building has a large shear capacity due to the large number of walls. However, it is very brittle, and fails abruptly at a low drift ratio. Nevertheless, the FEMA P-2018 showed that this case study building has a rating indicating a relatively low seismic risk. By contrast, the loss and downtime assessment of the building showed that performance would fall short of the target recovery state of shelter-in-place after a 475yr return period earthquake and the target downtime to functional recovery of 4 months. Since the analysis using FEMA P-2018 suggests that the archetype building would perform better relative to other similar buildings, detailed analyses are recommended for any buildings of this type.
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