Lateral response evaluation of fiber-reinforced neoprene seismic isolators utilized in an unbonded application

This study examines the experimentally obtained lateral response characteristics of model scale square fiber-reinforced elastomeric isolator (FREI) bearings, which are intended to mitigate seismic induced forces on ordinary low-rise buildings. The bearings consist of an unfilled soft neoprene compound as the elastomer material and bidirectional carbon fiber fabric as the reinforcement. The bearings have been employed in an unbonded application, which means they are not attached to the upper and lower platens of the test machine. This unbonded application results in a stable rollover deformation, which decreases the effective lateral stiffness of the bearings and maximizes their efficiency as a seismic isolator device. Lateral load-displacement hysteresis loops of the FREI bearings with unbonded application are generally found to be comparable to that of conventional high damped steel reinforced bearings. The adequacy of the bearings has been verified in conformance with provisions of ASCE in 2005.