Effective Assessment of Inelastic Torsional Deformation of Plan-Asymmetric Shear Wall Systems

Torsional deformation may occur in plan-asymmetric wall structures during seismic events. In most current seismic design codes, the torsional deformation is handled using the concept of design eccentricity, in which design loads may be excessively amplified. This approach has limitations in accurately estimating the torsional deformation of the plan-asymmetric structures, mainly because it is based on linear elastic material behavior. In this paper, we propose a simple method that can accurately evaluate the inelastic lateral displacement and rotation of plan-asymmetric wall structures and is suitable for use in the displacement-based design method. The effectiveness of the proposed method is verified by comparing its predictions with the results of rigorous time history analyses for a model problem. The comparison shows that the proposed method is able to provide accurate estimates of the inelastic torsional deformation for the plan-asymmetric wall system, while requiring less computational cost than the time history analysis.