The Influence of Shape Factors on the Lateral Response of Fiber Reinforced Isolators of Different Boundary Conditions: Finite Element Analysis

Steel-reinforced elastomeric isolators (SREIs) represent a widely adopted seismic isolation technique. However, their suitability for conventional residential structures, particularly in developing nations, is limited due to the associated high costs. This cost arises from the necessity of incorporating thick steel plates and substantial energy consumption during manufacturing. In contrast, fiber-reinforced elastomeric isolators (FREIs) present a novel elastomeric isolation solution. Rather than relying on steel lamina, FREIs utilize thin layers of fibers for vertical reinforcement. Compared to SREIs, FREIs offer a distinct advantage with their significantly reduced weight and the possibility of cost-effective manufacturing through cold vulcanization. FREIs can be installed between the upper structure and the foundation without the need for bonding or fastening, a configuration known as "unbonded application" resulting in substantial cost savings. Additionally, in scenarios without steel supports or with partial bonding, FREIs exhibit enhanced energy dissipation due to the friction generated between the isolator and the structure surfaces. This study presents a finite element analysis of FREIs, considering various shape factors and different boundary conditions (bonded, unbonded, and partially bonded). Each device underwent static analysis, experiencing a horizontal displacement of up to two times the overall height of the rubber pads while maintaining a constant vertical pressure. The outcomes of the study are assessed based on parameters such as horizontal maximum force, horizontal stiffness, horizontal frequency, and horizontal period. This numerical investigation offers valuable insights into the lateral response characteristics of FREIs.