Experimental study of a scaled bridge model with a unidirectional rocking isolation bearing system (Uni-RIBS) through shaking table tests

This study presents the experimental results on a scaled bridge model with a newly proposed unidirectional rocking isolation bearing system (referred to as Uni-RIBS) on a shaking table. The bridge model features one superstructure girder and four bearings. The experimental input encompassed a variety of recorded, design, and harmonic ground motions, characterized by differing peak accelerations, with or without vertical components, and time-scaled attributes. The superstructure girder's mass was altered for two conditions (full and half). The test results validate the rocking mechanism inherent in the Uni-RIBS and demonstrate the analytical model's accuracy in predicting the system's dynamics, including its negative stiffness, mass-independent, and energy dissipation characteristics during bearing rotation reversals. Additionally, this study examines the effectiveness of a simplified numerical model in varying complexities for predicting the seismic responses of the bridge model.