Response of base-isolated buildings incorporating fluid viscous devices to near-fault earthquakes

The effects of simulated near-fault earthquakes on the response of base-isolated structures are analysed in this paper. Two types of physically realisable near-source ground motion models were examined in this study, both represented by trigonometric “forward and back” pulses produced by a blind-thrust fault. The base isolation system considered was a special technology coupling steel-Teflon sliding bearings and silicone fluid-viscous dampers. The following analyses were carried out: a) evaluation of the spectral response of SDOF oscillators, incorporating the technology above, to the two types of simulated pulses; b) comparison of the resulting spectra with the corresponding curves derived from artificial accelerograms generated from the design spectrum of the Italian seismic Standards; c) application of the most critical near-fault signals highlighted by the spectral analysis to the computational model of an actual base-isolated building. A report on these analyses is presented herein, along with a final evaluation of the near-fault earthquake effects based on the results of non-linear dynamic analyses performed at point c).