Seismic Force Modification Factors for Concrete-Filled Coupled Composite Plate Walls: Evaluation for the National Building Code of Canada

Concrete-filled coupled composite plate walls, used as seismic force-resisting systems in high-rise buildings, can substantially expedite construction schedules. This system was recently incorporated into ASCE 7-22 with a high response modification coefficient (R) of 8.0. However, its adoption into the National Building Code of Canada requires validation of its ductility-related (Rd) and overstrength-related (Ro) force modification factors. This paper addresses this need by employing the recently proposed Performance-Based Unified (PBU) procedure, a new Canadian methodology for quantifying seismic performance factors. The PBU procedure is applied to a comprehensive suite of archetype structures, including planar and C-shaped wall configurations, to thoroughly evaluate the system’s performance under Canadian seismic hazard. The analyses demonstrate that Rd =5.0 and Ro =1.6 are appropriate for this system. These factors are shown to provide an acceptable margin against collapse, satisfying the life safety and collapse prevention performance objectives stipulated for the Canadian seismic design.