Design and Component Testing of an SMA-Based Seismic Control Device

This study explores the development of an SMA-based self-centering viscous damper in order to mitigate dynamic response of structures subjected to multi-level seismic hazards and to enhance their post-earthquake functionality. The device, named as Superelastic Viscous Damper (SVD), exhibits both re-centering and energy-dissipating capabilities and consists of SMA bars and a viscoelastic (VE) damper. SMA elements are mainly used as re-centering unit and the viscoelastic damper is employed as energy dissipation unit. The VE damper consists of two layers of a high damped (HD) blended butyl elastomer compound chemically bonded to steel plates. Energy is dissipated through the shear deformation of elastomeric material by hysteretic damping. Experimental tests are conducted to characterize the behavior of both SMAs and elastomeric material and assess the influence of displacement amplitude and loading frequency on the material behavior. A parametric study is conducted to evaluate the effects of various design parameters of SVD on the overall behavior of the device. A prototype of the SVD is designed and fabricated. Results of the experimental tests on the prototype device show that a judiciously designed SVD can provide considerable amount of energy dissipation with almost excellent self-centering capability.