Date: Jun. 5, 2024
Abstract
Shear walls have always been the SFRS of choice for high-rise concrete buildings in Canada. Early designs utilized highly compressed thin rectangular walls; however, the need for inelastic drift capacity (ductility) has made core walls the predominant shear wall system in Canada for the past four decades. This system has recently become popular on the west coast of the United States where nonlinear analysis is used to design the system. Canadian practice is to use linear dynamic analysis combined with simplified procedures to account for nonlinear effects such as: (1) an appropriate displacement-based approach for high-rise shear wall buildings (adopted in Canada two decades ago); (2) accounting for inelastic effects of higher mode shear; (3) design of gravity-load resisting frames for seismic deformation demands; (4) accounting for additional drifts due to soil/rock flexibility under shear wall foundations; (5) analysis of subterranean levels accounting for nonlinear floor diaphragms, and; (6) dynamic force demands due to sloped gravity-load columns. These ‘made in Canada’ simplified solutions, which in some cases give more rigorous solutions than nonlinear dynamic analysis, will be reviewed. In addition, the following current issues will be briefly discussed: (7) new provisions permitting highly compressed rectangular walls with no ductility in regions with low seismic displacement demands; (8) satisfying the new additional performance requirements of NBC Article 4.1.8.23 for more frequently occurring ground shaking, and; (9) the design of modern buildings with unusual irregularities that are not covered by the provisions of the current Building Code.
Presenter’s Biography:
Dr. Perry Adebar, P.Eng. is Professor of Structural Engineering at the University of British Columbia, where he has conducted research on the seismic design of concrete shear wall buildings for the past 30 years. He is currently chair of the national Standing Committee on Earthquake Design (SC-ED), which writes the earthquake design provisions for buildings in the National Building Code of Canada; vice-chair of Technical Committee CSA A23.3, which writes the Canadian Standard for the structural design of concrete buildings, and; chair of the Task Group responsible for Clause 21 Special Provisions for Seismic Design of concrete buildings. Dr. Adebar is the lead author of the BC professional practice guidelines on the Structural Design of Tall Concrete Buildings.
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