Shaking table test of the seismic performance for railway simply-supported girder bridge isolated by self-centering bearing

Abstract

In order to solve the problem of the residual displacement of a railway simply-supported girder bridge and realize the aim of a rapid recovery in traffic after earthquake events, we designed a self-centering seismic isolation bearing and created a typical simply-supported girder bridge model with 1/10 ratio. Three peak ground acceleration (PGA) shaking table tests were performed, with the test procedures further described in detail. The test results show that the bearing provides an overall good self-centering performance. Other than the case of a 0.5 g transverse earthquake, where the bearing remains outside of the sliding surface and therefore cannot be self-centering, all the tests show that the bearing is completely self-centering. At the same time, during all the earthquake scenarios, the main structure of the bridge was not damaged in any discernable way, the longitudinal frequency did not change, and the transverse frequency decreased given that the bearing remained outside of the sliding surface. In addition, it was found that the large bearing displacement in the longitudinal direction may lead to a collision of adjacent girders, resulting in a sharp increase in the acceleration of the girders. In cases without collisions between the girders, the acceleration of the girder is effectively reduced compared with the acceleration of the pier top. The results also show that the pier can be effectively protected by the self-centering bearing, as well as indicating that the reinforcement strain of the pier does not reach the yield value under all tests. Due to the large displacement of the bearing, it is necessary to increase the allowable displacement or install a limiting device. Finally, the finite element model (FEM) of the test model is established, with the calculation results compared with the test results, in this way proving the correctness of the FEM and providing a reference for designing the seismic isolation of the railway simply-supported girder bridge.