Seismic performance and height limits of ductile reinforced masonry shear wall buildings with boundary elements

Abstract

The National Building Code of Canada, NBCC-15 has recently added a new Seismic Force Resisting System (SFRS) category, ductile shear walls, for Reinforced Masonry (RM) buildings. Although it was assigned a higher ductility-related force modification factor compared to that of moderately ductile walls, NBCC-15 assigned the same building height limits for the ductile and moderately ductile RM walls. This study aims to assess (i.e. numerically) the seismic performance and collapse capacity of ductile RM buildings, having heights exceeding the code limit, built using ductile RM shear walls with boundary elements as the SFRS. The main objective is to propose height limits based on solid and objective seismic performance acceptance criteria. In this regard, six archetype buildings with varying heights are designed according to CSA S304-14 with ductile RM structural walls having confined boundary elements. The reference buildings are located in two regions representing the high and moderate seismicity levels of NBCC-15. The seismic performance is evaluated using nonlinear pseudo-static pushover and Incremental Dynamic Analyses (IDA). The quantification of seismic performance and collapse capacity is executed using the procedure outlined in FEMA P695. This research study contributes to the understanding of the seismic performance and collapse capacity of ductile RM shear wall buildings with boundary elements. It provides practical design recommendations to enhance the overall system performance. In addition, the study proposes a simple, yet efficient nonlinear numerical macro-modeling approach for RM shear walls. Finally, based on the findings of this study, it is suggested to assign a 70 m limit for the height of buildings in moderate seismicity regions and a 50 m limit for the buildings in regions with high seismic hazard.