SHAKING TABLE TESTS OF THE SEISMIC POUNDING EFFECT ON A SMALL RADIUS CURVED BRIDGE UNDER NEAR-FAULT GROUND MOTIONS

A two-segment multi-span curved bridge with a small radius were established and a series shaking table tests were carried out in order to reveal the mechanism of earthquake damage due to adjacent girder pounding of small radius curved bridges. The paper analyzed the effect of the change of adjacent segment period ratio on such responses as the displacement at the end of the curved bridge, the relative displacement of pier and girder and the pounding force under different ground motions. The dynamic response of adjacent girder pounding effects are analyzed under the influence of lateral eccentric effect of single column pier excited by near fault earthquake. There are four main conclusions in this paper. Firstly, the pounding effect of adjacent girders firstly increases and then decreases with the increase of the period ratio under near-fault pulse earthquakes. Secondly, the pounding response increases gradually with the decrease of the period ratio of adjacent girders under the near-fault non-pulse ground motions and far-field earthquake motions. Thirdly, the lateral eccentricity of the single-column pier at the bottom of the girder increases the change of the movement form of the main girder under the earthquake action, resulting in an increase of torsion and lateral displacements. Fourthly, such increased torsion and lateral displacements often result in non-uniform pounding effect appear, which aggravates the local damage of the main girder. The major findings of this paper can provide a scientific basis for better seismic design of curved bridges considering seismic pounding.