Influence of ground motion scaling methodology and lead rubber bearing seismic isolator modelling technique on seismic response of an isolated structure

In this study, the maximum isolator displacement (MID), maximum isolator force (MIF), and maximumacceleration (MA) values that occur at the isolation level in seismically isolated structures were investigatedusing the nonlinear response history analyses (NRHA) by considering four different scaling methods. Bothhorizontal components of the ground motion records scaled with different scaling methods were appliedsimultaneously to the isolation unit modeled with lead rubber bearing, and bi-directional analyzes were performed. In the analyses, lead rubber bearings were modeled with two different approaches as the casedeterioration due to the heating effect in the lead core is considered (Temperature Included, TI) and the caseit is not considered (Boundary Analysis, LB-UB). In the analyses, four different Q/W ratios (0.75, 0.90,0.105, and 0.120) representing the isolation unit strength, and five different Tiso (2.5s, 2.75s, 3.0s, 3.25s, and3.5s) representing the isolation period were taken into account. As a result, while the variation in the scalingmethods does not create a significant change on the maximum isolator forces, it is observed that it can causechanges up to 25% in the maximum isolator displacements and maximum acceleration values. Thisdifferentiation is negligibly affected by how the seismic isolator is modeled.