Pseudo-dynamic experimental study on seismically isolated prefabricated RC structure with roller-bearing subjected to mainshock-aftershock sequences

Abstract

For the series seismic isolated structure with isolation bearings at the top of the frame columns on a certain floor, the differences in mechanical properties between it and its corresponding aseismic structure are mainly caused by the isolated system consisting of the isolation bearing and column beneath it. Herein, taking the prefabricated isolated system as the research object, a novel roller-bearing (RB) with a displacement-restricted device and a different type of column-to-column connection joint (CCCJ) are presented, the two are both applied to form seismically isolated prefabricated reinforced concrete (RC) structure using roller-bearing (SIPRCS-RB). The seismic performance of the prefabricated isolated system under mainshock-aftershock sequences (MS-AS) is evaluated using a pseudo-dynamic experiment. The strain, overall bearing capacity, and cumulative hysteretic dissipated energy (CHDE) of the concrete at the connection joint in the prefabricated column have not changed significantly, compared with corresponding parts in the cast-in-situ column, while the strain of the rebars has decreased considerably, indicating that the proposed CCCJ is reliable and has excellent seismic performance. Contrasting the responses of the prefabricated column and the RB under a single mainshock with that under the MS-AS, when the aftershock strikes, the CHDE of both components will increase markedly due to the previous damage induced by the mainshock, but the increase in deformation is relatively minor; the larger the peak ground acceleration (PGA) of the mainshock is, the greater the increase in CHDE of the components under aftershocks. Therefore, for the SIPRCS-RB, the effect of the MS-AS on seismic performance should be considered.