Quantifying the Ductility-Related Force Modification Factor for 10-Story Timber–RC Hybrid Building Using FEMA P695 Procedure and Considering the 2015 NBC Seismic Hazard

Abstract

In this work, a 10-story uncoupled (10S-U) hybrid seismic force resisting system, consisting of cross-laminated timber (CLT) walls and reinforced concrete (RC) beams, is considered. Required design ductility factor Rd, in congruence with the National Building Code of Canada, was developed using FEMA P695 collapse risk procedure. Two trial Rd factors, Rd=2 and Rd=3, were first used to design the hybrid building for seismicity of Vancouver, BC, and 3D numerical models were developed in Open System for Earthquake Engineering Simulation (OpenSees) finite element framework. The energy dissipation of the structural system was enhanced using buckling restraining brace hold-downs and energy dissipator connection between the panels. The rocking response mechanism governed and, as a result, the cyclic pushover results show recentering capability. A suitable set of 30 ground motion records that reflect the seismic hazard of Vancouver, British Columbia, was selected in congruence with the 2015 National Building Code of Canada (NBC). Using incremental dynamic analysis, the collapse risk and collapse margin ratios were obtained to check the suitability of the two proposed Rd factors. The Rd=2 factor was shown to be acceptable for the 10S-U structural system.