Seismic Performance of Superelastic SMA Damper Retrofitted Building

Nonlinear dampers are well known retrofitting system for the building structure, to mitigate seismic hazard. In past, among different type of nonlinear dampers, metallic yield dampers gain significant attention due to its high energy dissipation capacity. However, it has been observed while yield damper reduces floor displacement, but increases floor acceleration and leaves large residual displacement at the end of ground motion. Present study focuses on the application of shape memory alloy (SMA) dampers as an alternative to the yield damper, for retrofitting of building structure under seismic loading. Thus, response analyses are performed for nonlinear building structure without and with yield damper or SMA damper, under a large number of ground motion. Vibration control efficiency of yield and SMA damper are estimated in terms of the absolute maximum values of the floor acceleration, interstory drift ratio, and residual displacement. Response parameters are estimated over wide range of parameters of damper, building structure, and ground motion. Parametric study results revealed that yield damper provides very less acceleration control efficiency and some of cases it become more than uncontrolled structure. In contrast SMA damper slightly improves the acceleration control than yield damper (almost 14 %). In Comparison to the yield damper, SMA damper reduces the interstory drift ratio by 38 % and residual floor displacement by 47 %. Therefore, SMA damper provides major advantage in floor displacement reduction over yield damper, and acts as better re-centring device for seismic retrofitting application.