Higher Mode Effects on Shear Amplification and Seismic Performance of RC Shear Walls Subjected to Western North American Ground Motions

In this study, the inelastic shear amplification and seismic performance of reinforced concrete shear walls (RCSWs) in western North America, designed according to Canadian seismic codes, were evaluated using nonlinear time history analyses (NLTHAs) and performance‐based design guidelines. The walls ranging from 5 to 40 stories were modeled using computationally efficient numerical methods that account for nonlinear flexural‐axial coupling, trilinear hysteretic shear behavior, and modal damping. These methods were validated against experimental data and advanced finite element techniques. Ground motions were selected using a multiple‐event conditional spectrum approach to capture the complexity of seismic sources. The results indicate that while collapse probabilities remain low and most walls exhibit satisfactory shear performance, variations are observed in predicted top displacements and inelastic shear amplification factors. Some of the studied cases do not meet performance‐based shear requirements. Nevertheless, recent experimental evidence on Canadian RCSWs suggests that high shear amplification does not necessarily lead to brittle shear failure. Furthermore, the assumption of low shear demand in most cycles during crustal ground motions appears invalid for long‐duration, high‐intensity interface events. These findings emphasize the need for further large‐scale experimental investigations of RCSWs under subduction zone seismic events to refine performance‐based evaluation methods.