Seismic Isolation of a Shear Wall Structure Using Rectangular Fiber-Reinforced Elastomeric Isolators

The seismic response of a 2-story reinforced concrete shear wall structure seismically isolated using unbonded rectangular fiber-reinforced elastomeric isolators (FREIs) is investigated. Using rectangular isolators, rather than square or circular, for buildings with masonry or reinforced concrete structural walls allows a more uniform distribution of the gravity loads and eliminates the requirement of additional wall beam elements. Time history analyses are conducted for both fixed-base (FB) and base-isolated (BI) configurations using 10 earthquake ground motions, selected to match the design response spectrum. The properties of the isolators are taken from lateral cyclic test results carried out on scale model FREIs. A pivot-elastic model, previously introduced by the authors, is used to model the lateral response of the isolators in the time history analyses. The peak response values of the BI structure are significantly reduced compared with the results for the FB structure. It is concluded that unbonded rectangular FREIs can be effectively designed and used to seismically isolate masonry or reinforced concrete shear wall structures.