Experimental Evaluation of Seismic Performance of SMA Bridge Restrainers

Report No. CCEER-04-2Tests were conducted at the University of Nevada Reno Large Structures Laboratory, in cooperation with Georgia Institute of Technology, to determine the effect of shape memory alloy (SMA) cable and rod restrainers on the seismic performance of in-span hinges of a representative multiple-frame concrete box girder bridge subjected to earthquake excitation. Another objective of this study was to compare the performance of SMA to steel restrainers as restraining devices to reduce hinge displacement. Data collected from SMA restrainer experiments was compared to information gathered in a previous University of Nevada, Reno study on the performance of steel restrainers. The SMA restrainers showed promise as restraining devices to limit hinge displacement in bridges and the ability to dissipate energy. Under equivalent loading, the steel restrainers produced relative hinge displacement approximately three to four times that of the SMA restrainers. The hysteretic damping that was seen in the larger ground accelerations showed the materials ability to dissipate energy with small residual strain