Performance-based seismic assessment and retrofit of mid-rise buildings

The Province of British Columbia (B.C.), which is located in a region with a high risk of significant seismic activity along the West Coast of Canada, has implemented a program to mitigate the seismic risk for over 750 provincial school buildings. In order to provide a cost-effective tool for seismic assessment and retrofit of these buildings, a state-of-the-art probabilistic performance-based methodology based on nonlinear dynamic incremental analyses has been developed. The latest implementation of this methodology: a set of guidelines called the Seismic Retrofit Guidelines 2nd Edition (SRG2), was issued in 2013 and includes provisions to assess and retrofit mid-rise university and college buildings belonging to the British Columbia Ministry of Advanced Education (MOAE). To implement this performance-based methodology for mid-rise buildings requires the use of nonlinear analyses of more sophisticated building models compared to low-rise buildings. This methodology also demands significant computational capabilities in order to complete all the parametric analyses necessary to define the seismic risk of these structures. Due to these factors, the original SRG methodology was adapted to develop a unique set of guidelines specifically for the performance-based assessment and retrofit of mid-rise concrete shearwall buildings. Also developed for use with the guidelines is a highperformance tool that can be used for the rapid evaluation of the seismic risk of these buildings. This tool along with the method developed in this paper allows engineers to benefit from the advantages of probabilistic performance-based design by simplifying and expediting the process of performing sophisticated incremental nonlinear analysis.