Seismic Performance Assessment Of Highway Bridges Isolated By Negative Stiffness Bearings With Shape Memory Alloy

The current paper aims to propose a description of the negative stiffness bearings (NSB) with shape memory alloy (SMA) in the conventional friction-based sliding bearings pot bearings. The negative stiffness is achieved using the pre-compressed springs while the SMA is adopted to improve the re-centering ability of pot bearings. The force-displacement relationship of this bearing are derived based on both analytical equations and numerical simulations. The 3-D finite element model of a selected highway bridge is modeled in the software OpenSees. Various engineering demand parameters (EDPs), namely bearing displacement, girder displacement, shear forces and moments, are selected to evaluate the seismic performance of a highway bridge. The results from nonlinear time-history analysis show that the SMA and negative SMA bearing are more effective than the conventional pot bearing to reduce the peak and residual displacement greatly. In some cases, the negative SMA bearing are also effective to reduce the shear forces and moment.