Design Examples of Controlled Rocking Braced Frames for Low-Rise Buildings in Canadian Regions of Low Seismicity

Modern earthquake engineering practices rely on inelastic behavior within the lateral force resisting system to dissipate energy and prevent building collapse. This inelastic behavior often causes buildings to suffer permanent structural damage and residual drifts after design-level seismic events. Controlled rocking braced frames (CRBFs) have been shown to control damage and limit residual displacement more effectively by allowing selected columns to intentionally uplift. Regions of low seismicity present unique considerations for CRBF design due to the differing relative design requirements of the self-centering mechanisms, specifically self-weight and energy dissipation. Existing preliminary design guidance and research are promising, but there are few comprehensive design guides and code provisions globally, and none in Canada. In this paper, a step-by-step design process aligned with Canadian codes and standards is presented at a level readily interpreted by consulting structural engineers in a design office setting. These steps are then implemented to design a suite of CRBF building archetypes reflective of common low-rise, low-seismic-category steel buildings in Canada. Nonlinear response history analysis is conducted using advanced models of the low-rise buildings subject to ground motions typical of low-seismic-hazard regions. The structures’ performance found by these analyses is assessed and compared to the targets expected for code-compliant designs. The outcomes of this paper highlight the technical and economic viability of CRBFs in some of the most populous areas of Canada, and by extension, the world.