Modeling and Evaluation of a Seismically Isolated Bridge Using Unbonded Fiber-Reinforced Elastomeric Isolators

An unbonded fiber-reinforced elastomeric isolator (U-FREI) is a relatively new type of elastomeric bearing that can be implemented as a seismic isolator for bridges. U-FREIs possess beneficial characteristics, including their potentially low-cost and light-weight construction. Individual U-FREIs can be rapidly produced as they can be easily cut from large sheets to the required size and shape, which is an attractive feature for accelerated bridge construction. The objectives of this paper are to introduce a noniterative analytical model to simulate the lateral response of U-FREI, and then to utilize the model to investigate the seismic response of a typical highway bridge isolated using U-FREI and compare it with a traditional non-isolated bridge. The isolated bridge demonstrated a resilient seismic behavior where all the bridge components remained elastic with no damage or residual deformation. The analytical results indicate that the seismic demand of the isolated bridge is reduced by up to 77% and 84% in terms of base shear and accelerations, respectively, as compared with the non-isolated bridge.