Abstract
This study investigates the variations in the mechanical properties of high-damping rubber bearings HDRBs on the dynamic response of multi-story seismic base-isolated building subjected to bidirectional near-fault ground motions. Variations in the mechanical properties of HDRB due to temperature, aging and scragging recovery are considered. Nonlinear response analyses of a six-story base-isolated building subjected to seven pairs of bidirectional near-fault ground motions with pulse type were conducted using finite element software. The nonlinear force-deformation behavior of isolator is modeled using a bilinear hysteretic curve considering non-deteriorating and deteriorating properties. Results of analyses are compared in terms of bearing displacement, base shear, force-displacement loops, top floor absolute acceleration and story drift. It was observed that the seismic response of base-isolated multi-story building is significantly influenced by the variation in mechanical properties of rubber bearing seismic isolators.