Experimental study of a highway bridge with shape memory alloy restrainers focusing on the mitigation of unseating and pounding

This paper presents an experimental study to investigate the performance of shape memory alloy (SMA) restrainers for mitigating the pounding and unseating of highway bridges when subjected to seismic excitations. Mechanical property tests of the SMA wire used in the restrainers are conducted first to understand the pseudo-elastic characteristics of the material. Then, a series of shaking table tests are carried out on a highway bridge model. The structural responses of the highway bridge model equipped with SMA restrainers, installed in the form of deck-deck and deck-pile connections, are analyzed and compared with the uncontrolled structures. The test results of this study indicate that the SMA restrainers are not only effective in preventing unseating but also in suppressing the seismic-induced pounding of the highway bridge model used in this study.