Analytic solution and shaking table test on the study of bridge structure with functional bearing system

This study presented a state-space based analytical method to predict the displacement demand for bridge with functional bearing system, and its accuracy was successfully verified by the shaking table test results. A simplified two-degree-of-freedom system was adopted to account for the stick and sliding states of the rubber bearing, so that shear and sliding deformations of the rubber bearing were differentiated. Besides, in order to examine the rationality of the proposed approach, a shaking table test of a simply-supported bridge model was carried out to obtain the properties of laminated rubber bearing, including lateral stiffness, friction coefficient, and inherent damping. It was founded the lateral stiffness should be defined by a function of lateral shear strain, rather than a constant value in all seismic events. The static and dynamic friction coefficient for rubber against concrete surface are about 0.5 and 0.35, respectively. The inherent damping is 7% on average before sliding. The parameters mentioned above were applied into the proposed simulation model. It is confirmed the maximum and residual displacement as well as the maximum acceleration of girder were effectively predicted. In the future, both unseating length and shear force demand could be further investigated by the proposed model.