Seismic response evaluation of self-centering structural systems

Recent moderate and large earthquakes have caused significant damages on building systems. Aiming at minimizing structural and nonstructural damages, structural systems with self-centering capability were developed recently. In order to improve our understanding regarding the seismic performance of self-centering structural systems and to provide information necessary for the development of performance-based design guidelines, this study intends to evaluate and quantify the seismic performance of self-centering structural systems within a probabilistic-based framework.; Based on nonlinear response history analyses, this study investigates the characteristics of the seismic response of four types of self-centering SDOF systems. In addition, the conventional elastoplastic and stiffness-degrading systems are also incorporated for comparison. The results on inelastic displacement ratio are closely examined. Mean inelastic displacement ratios as well as statistical results are presented and compared with the conventional elastoplastic or stiffness-degrading hysteretic system, and the effect of various structural or geotechnical parameters, including period of vibration, lateral strength, post-yielding stiffness, site conditions and ground motion duration are fully investigated. Furthermore, in order to provide practical approaches for rapid evaluation of displacement demands on self-centering systems, simplified equations are proposed and nonlinear regression is performed. Finally, the probabilistic characteristics of inelastic displacement demands are quantified within a simplified probability-based framework.; This study also investigates the effect of self-centering hysteretic behavior on the seismic performance of MDOF structures. A generic MDOF structural model is constructed using the RUAUMOKO (Carr, 2003) to evaluate the effect of self-centering concrete walls on the seismic response of frame-wall structural systems. A large number of incremental dynamic analyses (Vamvatsikos and Cornell, 2001) are performed and the results are closely examined. A comprehensive parametric study is carried out to evaluate the effects of different structural parameters. In addition, by recognizing the conceptual similarities between the unbonded post-tensioned walls and flexible rocking structures, the MDOF model is further simplified using the rocking approximation of the base gap opening and continuum beam-column model. It is demonstrated that, by considering only the first several modes, the seismic response of the MDOF structures can be very well captured by the rocking response of continuum beam-column element.