Experimental and Numerical Characterization of a Circular Unbonded Fiber-Reinforced Elastomeric Isolator With High-Damping

Fiber Reinforced Elastomeric isolators (FREis) represent a novel category of elastomeric seismic isolators. in contrast to conventional Steel-Reinforced Elastomeric isolators (SREis), FREis incorporate slender layers of fibers instead of steel laminates to provide vertical reinforcement. These isolators can be utilized in various configurations, including bonded, unbonded, and partially bonded setups. in the unbonded configuration, the isolator is positioned between the superstructure and the foundation without bonding or fastening. The shear load transfer relies on the friction generated between the isolator and the structure. This application is characterized by rollover deformation, which reduces horizontal stiffness and enhances the damping capacity of the isolator compared to its bonded counterpart. This study proposes a combined numerical and experimental approach to characterize the lateral behavior of FREis. A preliminary numerical model, based on simple material tests, is presented to predict the horizontal characteristics. Subsequently, a prototype is fabricated and subjected to experimental tests, with the results compared to the numerical predictions. The outcomes of this research underscore the robustness of the numerical model, which can be employed both for predicting lateral behavior and anticipating future structural applications.