Seismic Behaviors of Double-Column Pier-Bearing System Based on Shaking Table Tests

In recent years, with the widespread application of double-column pier bridges, their seismic performance has attracted increasing attention. However, traditional seismic performance analysis treats piers and bearings as separate research objects, lacking an integrated investigation, which fails to provide accurate guidance for practical engineering projects. This paper aims to study the seismic performance of the double-column pier-bearing system based on shaking table tests. The results show that: (1) The sensitivity of the system’s seismic performance indicators to bearings, ranked from highest to lowest, is: acceleration amplitude, damping ratio, displacement amplitude, and natural vibration frequency. (2) The cumulative effect of long-duration earthquakes is significant. Even with a lower peak ground acceleration, the displacement response may be greater than that of short-duration earthquakes with a higher peak ground acceleration. (3) Wavelet transform can accurately identify that the natural vibration frequency of systems equipped with different bearings ranges from 0.5 to 1.2 Hz, and the damping ratio ranges from 3% to 9%. (4) When the bearing thickness is increased from 21 mm to 42 mm, the system displacement response decreases from 11.41 mm to 10.28 mm. (5) Adding a 2 mm thick polytetrafluoroethylene layer to the conventional laminated rubber bearing can reduce the displacement response by 19%. The research findings indicate that it is necessary to conduct a feasibility analysis of bearing selection based on site characteristics.