Analytical studies of shape memory alloy dampers for structural control of base isolated bridges

ABSTRACT

Base isolation provides a very effective passive method of protecting bridges from the hazard of earthquake. The proposed smart isolation system combines the laminated rubber bearing with the device made of shape memory alloy (SMA). The constitutive law for superelastic material is extended to describe a hardening of the stress-strain relation of SMA at large strain levels. The smart base isolation utilizes the different responses of the SMA at different levels of strain to control the displacements of the rubber bearing at various excitation levels. At the same time the hysteresis of the alloy is used to increase the energy dissipation capacity. The performance of the smart base isolation is compared with the responses of laminated rubber bearing with lead core to quantify the benefits of applying SMA for isolation of elevated highway bridge. (AU)