SELF-CENTERING CAPABILITY OF SHAPE MEMORY ALLOY (SMA)- BASED SUPERELASTICITY-ASSISTED SLIDER (SSS)

The self-centering capability, emphasized in design codes as a fundamental feature of aseismic isolation systems, is investigated for the Shape memory alloy (SMA)-based Superelasticity-assisted Slider (SSS). Restoring force in SSS is associated with austenitic SMA wires in order to properly re-center flat sliders. Energy considerations are examined first as an insight into the problem, revealing also the governing parameters. The self-centering capability is then investigated through an extensive parametric study of the isolated structures idealized as single-degree-of-freedom systems subjected to a large group of recorded earthquakes. According to the results obtained from extensive nonlinear time-history analyses,residual displacement after an earthquake and the cumulative build-up of displacements after a series of successive earthquakes depend on both structural properties and ground motion characteristics. SSS exhibits an acceptable self-centering capability, satisfying code provisions.