Re-centering capability of partially self-centering structures with flag-shaped hysteretic behavior subjected to near-fault pulsed ground motion

Abstract

Self-centering structures have become the focus of current research in earthquake engineering due to their excellent re-centering capability. The re-centering capability primarily influences the residual displacement of structures that is an essential index for assessing the performance of post-earthquake functional and withstand subsequent seismic events of structures. The main purpose of this paper is to investigate the re-centering capability of partially self-centering structures with flag-shaped hysteretic behavior subjected to near-fault pulsed ground motion. To this end, the current provisions on residual displacement of structures were first introduced. Then two self-centering energy dissipation braces (SCEBs) with fully re-centering capability and partially centering capability are developed, and their hysteretic behavior are investigated by quasi-static cyclic loading tests. To capture the flag-shaped hysteretic behavior of such self-centering structures, a mathematical restoring force model based on the Bouc-Wen model is developed. It is found that the self-centering capacity of a partially self-centering structure is inversely related to the energy dissipation capacity, resulting in a reciprocal effect on the maximum and residual deformations of the structure under earthquakes. The influence of the critical parameters (including the energy dissipation ratio (β), the post-yield stiffness ratio(α) and pulse period (T_p)) on the re-centering capability of the model is further investigated by using mathematical and statistical methods. Based on these results, the design recommended values of β for models with different α are given, furthermore, a simplified calculation formula for residual displacement of partially self-centering structures is established based on mathematical statistics.