Seismic design and performance evaluation of low-rise steel buildings with self-centering energy-absorbing dual rocking core systems under far-field and near-fault ground motions

Abstract

This research focuses on seismic design and performance evaluation of low-rise steel buildings with self-centering energy-absorbing dual rocking core systems (denoted as SEDRC systems) under far-field and near-fault ground motions. The SEDRC system consists of two rocking cores (RCs) and several shear friction spring dampers (SFSDs). These SFSDs are located between the two RCs and arranged over the height of the SEDRC system to absorb energy and provide a self-centering feature. The two RCs are considered as two buckling restrained braced frames in this paper, which are utilized to obtain uniform inter-story drift distribution in buildings. The two RCs can also act as a backup lateral force-resisting and energy-dissipation system if necessary. A direct displacement-based design (DDBD) procedure is introduced for the SEDRC system. A physical test was conducted to investigate the stability of the SEDRC system under repeated loading with near-fault loading protocol. The test results show that the SEDRC specimen can get stable self-centering behavior under repeated rounds of tests, indicating that the SEDRC system can be fully recoverable against multiple earthquakes before the development of the bearing action in SFSDs. The computational model of the SEDRC system was created and verified with the test results. A three-story representative building was designed through the proposed DDBD method, and the numerical models of the building were generated using the verified modeling method. Forty far-field ground motions and twenty near-fault ground motions were selected to perform Nonlinear Dynamic Analyses (NDA) on the designed building. The NDA results show that the designed three-story SEDRC system can satisfy the drift limit under DBE far-field excitations. And the designed SEDRC system can also survive and achieve small residual drifts subjected to the fault-normal components of the selected near-fault excitations and MCE far-field excitations.