Shaking table test study on seismic performance of curved bridge with concave island-type variable pier height

The application of small-radius curved bridges in urban interchange ramp bridges and mountainous bridges is becoming increasingly common. Among them, the curved bridge with concave island-type variable pier height is widely used in mountainous areas since it can adapt to undulating terrain. However, previous post-earthquake investigations have shown that the irregular spatial structural characteristics of this bridge make its seismic behavior exceptionally complex, resulting in more severe damage. Therefore, the seismic performance of the curved bridge with concave island-type variable pier height is investigated by conducting a shaking table test in this paper. Taking a typical four-span curved continuous girder bridge with concave island-type variable pier height as the prototype bridge, a 1/20 scale model is designed and made, and the shaking table test under the ground motion action is carried out to study the influence of ground motion input angle, near-field and far-field ground motions and seismic intensity on this curved bridge. The experimental results show that when the seismic input angle is close to the connecting line direction between the mid-high pier and the adjacent side pier, the overall response of this curved bridge is relatively large. Under the action of different near-field and far-field ground motions, the near-field ground motion of the velocity pulse magnifies the seismic response of this curved bridge more significantly than the far-field ground motion. In addition, with the increase of peak ground motion (PGA), the bridge segment with large stiffness (including the short and mid-high piers) exhibits a larger seismic response, which requires more attention in seismic design.