Modeling of high damping laminated rubber bearings in base isolated layers using bi-linear force restoring characteristics

High damping laminated rubber bearings are highly popular in seismic isolation application. However, due to the nonlinear dependency of the force restoring characteristics on shear strain, energy balance methods cannot be applied to evaluate the response of the isolation layer. Therefore, by replacing the complex restoring force characteristics of high damping rubber bearings with a simple bi-linear model, energy balance methods can be applied. In this paper, several replacement methods are compared in reproducing the accuracy of the response of the isolation layer using time history analysis and considering different earthquake motion phase characteristics and shear strain conditions.