Effect of Temperature on the Response of Unbonded Fiber-Reinforced Elastomeric Isolators

One of the most commonly used types of isolator is the steel-reinforced elastomeric isolator (SREI), but recent research has been completed on the use of fibers as a replacement to the steel reinforcement layers, reducing weight and potentially costs associated with isolation systems. These fiber-reinforced elastomeric isolators (FREI) can be used in bridges in an unbonded application, where they are placed between the bridge deck and bent cap beams. The use of isolators with bridges requires that the isolators are able to withstand the same negative temperatures that bridges located in cold climates will experience. This study investigates the behavior of unbonded fiber-reinforced elastomeric isolators (U-FREI) subjected to low temperature conditioning, representative of conditions that can be experienced in various regions throughout Canada. The response under lateral deformations expected during seismic events and vertical and rotational loading expected during regular operation were evaluated. The experimental results, in terms of effective stiffness and energy dissipated, indicate that the influence of temperature on the lateral, vertical, and rotational response of U-FREI is acceptable.