Story shear and torsional moment-based pushover procedure for asymmetric-plan buildings using an adaptive capacity spectrum method

• Conducting pushover analyses using a pre-calculated invariant load pattern.
• Load pattern based on the height-wise distribution of the story shear and torsional moment.
• Establishing the capacity curve based on the nonlinear deformed shape of the structure.

A single-run pushover procedure is proposed to assess the seismic response of asymmetric-plan buildings, when subjected to unidirectional earthquake ground motions. Effects of the higher and torsional modes are incorporated into an invariant load pattern, which is calculated based on the height-wise distribution of the modal story shear and torsional moment. In order to consider the effect of instantaneous changes in dynamic characteristics of the structure in the nonlinear phase, capacity curve of the structure is obtained using an adaptive capacity spectrum method. Results from numerical investigations indicate appropriate accuracy of the proposed procedure in capturing the relative displacement of structures when compared to the results from nonlinear response history analyses. The proposed load pattern can be utilized in seismic performance assessment software available for the engineering community for seismic assessment of asymmetric-plan buildings.