Shake Table Tests of Self-Centering Steel Braced Frame with Pretensioned Basalt Fiber Reinforced Polymers

Abstract

ABSTRACT Shake table tests were conducted on a three-story steel braced frame with pretensioned basalt fiber reinforced polymer (BFRP) under the mainshock and aftershock sequences. The BFRPs were firstly tested to evaluate their dynamic behaviors. Then the self-centering braced frame was excited to a series of scaled earthquakes whose PGAs range from 0.2 g to 1.2 g. Through the pinned connections in the tested frame, the self-centering braces (SCBs) with pretensioned BFRPs were the standalone components to dissipate the seismic energy. The results revealed that the BFRPs with slight performance degradation were suitable to provide the restoring force for SCBs even under the strongest earthquake intensity. SCBs with pretensioned BFRPs were efficient in preventing damage and reducing the residual drift ratios. Although the aftershock slightly amplified the accelerations of the tested frame, the self-centering braced frame with pretensioned BFRPs presented similar drift ratios under the aftershock and separate mainshock with the same PGA. Therefore, the self-centering steel braced frame with pretensioned BFRPs has favorable resilient seismic behaviors and could quickly restore its functions after a strong mainshock-aftershock sequence.