Influence of the Direction of Lateral Load on Fiber-Reinforced Elastomeric Isolators
Lecture Notes in Civil Engineering
Direction of loading, Earthquake engineering, Fiber-reinforced elastomeric isolators, Reinforced elastomeric bearings, Seismic base isolation
Fiber-reinforced elastomeric isolators (FREIs) consist of alternating horizontal layers of elastomer and fiber reinforcement. The low lateral stiffness and high vertical stiffness of these bearings make them ideal as seismic base isolators. FREIs can be used in a bonded or unbonded application. The top and bottom surfaces of bonded FREIs are attached to their supports, whereas unbonded FREIs (U-FREIs) are not. This allows U-FREIs to undergo rollover when laterally displaced. The rollover effect provides beneficial adaptive characteristics to the isolator. Many studies on U-FREIs only consider loading along the principal axes of the isolator. In this paper, a rectangular U-FREIs is loaded in the lateral direction at various angles from the principal axes. A constant vertical load is applied during cyclic lateral loading. The effect of angle of loading on the lateral stiffness and equivalent viscous damping are investigated and the results are discussed herein. A theoretical equation relating lateral stiffness with angle of loading, lateral displacement, shear modulus, and isolator dimensions is derived. Theoretical values are compared with experimental results to verify the equation.
Sinjari, S.; Stratton, N.; Cercel, J.; and Van Engelen, N.. (2023). Influence of the Direction of Lateral Load on Fiber-Reinforced Elastomeric Isolators. Lecture Notes in Civil Engineering, 241, 15-27.