Residual seismic capacity evaluation of earthquake damaged RC structures based on seismic capacity redundancy

A detailed evaluation method for residual seismic capacity of seismic damaged reinforced concrete (RC) building structures was proposed in this paper. This method overcomes the limitation of the existing methods, represented by the Japanese code, when applied on the structures composed of both shear failure and flexural failure structural elements (dual-failure mode structures). Based on pushover analysis and seismic capacity redundancy index of the structure, the proposed method can more comprehensively consider various performance changes due to the damage of the elements, and can determine the dominant failure mode and safety limit of the structures with dual-failure mode. By taking a real seismic damaged structure as example, the detailed method and the method of Japanese code were used to investigate its residual seismic capacity. It is found that the detailed method is more accurate for the structures with the dual-failure mode. For the structures dominated by the brittle failure mode, the prediction from the Japanese code is close to that from the detailed method. Nevertheless, for the structures dominated by the ductile failure mode, error of the Japanese code is considerable. In addition, by reasonably setting the construction slits to ensure the ductility of elements, the structural residual seismic capacity after the earthquake can be enhanced significantly. © 2020, Editorial Office of Journal of Building Structures. All right reserved.