Shake-Table Tests and Numerical Analysis of Steel Frames with Self-Centering Viscous-Hysteretic Devices under the Mainshock-Aftershock Sequences

Shake-table tests, subjected to mainshock-aftershock sequences, were conducted on a 1/3-scaled 3-story steel frame equipped with self-centering viscous-hysteretic devices (SC-VHDs) and its primary frame to investigate the effect of the aftershock on seismic performance. It was found that the SC-VHD can effectively reduce 30%-50% of the peak drift and 50%-80% of the residual drift, respectively. Additionally, the peak and residual drifts of the 3-story primary frame under the mainshock-aftershock sequences were more than those under the mainshock-only sequences, while the peak and residual drifts of the 3-story SC-VHD frame under the mainshock-only and mainshock-aftershock sequences were basically the same. A numerical simulation method for the SC-VHD frame was further developed and validated, based on which 6-, 9-, and 12-story SC-VHD frames were analyzed to investigate the seismic performance of medium- high-rise SC-VHD frames. Both shake-table tests and numerical analysis indicate that the peak and residual drifts of the 3-, 6-, 9-, and 12-story SC-VHD frames can meet the design objective under the mainshock-aftershock sequences.