Three-Dimensional Finite Element Analysis of Square Fiber-Reinforced Elastomeric Isolators (FREIs) under Lateral Loads

摘要

Fiber-reinforced elastomeric isolators (FREIs) are a relatively new type of laminated rubber bearing. FREIs utilize fiber material for the reinforcing layers instead of steel and thus have a lower weight compared to steel reinforced elastomeric isolators (SREIs). FREI bearings have a number of advantages over SREIs, which include superior energy dissipation capability. It is possible to use FREIs in an unbonded application, which eliminates the need of steel end plates. Due to the low flexural stiffness of the fiber reinforcement, unbonded FREIs undergo rollover deformation when loaded laterally. This type of deformation is found to increase the seismic mitigation efficiency of isolators. The lateral behaviour of unbonded FREIs is complex and currently few closed-form solutions exist to predict their response. Finite element analysis (FEA) can be employed to predict the vertical and lateral response behaviour of unbonded FREIs. This paper presents the results of 3D FEA of FREIs under lateral loading. Two previously tested square bearings are modeled and analyzed numerically and the results, in terms of lateral load-displacement curves, are compared with experimental results. Good overall agreement is observed between the experimental results and the FEA predictions. The stresses and strains in the bearings, obtained from FEA, are also presented and compared at selected lateral displacement levels.