Using Shake-Table Tests of a Large-Scale Self-Centering Tall-Pier Bridge to Investigate Seismic Performance

A novel self-centering (SC) tall-pier bridge system is proposed to improve the seismic performance of tall-pier bridges (pier height >40 m). The system features tall piers with unbonded post-tensioned (PT) tendons at both ends for connection to the foundation and girder. An externally mounted energy-dissipating connection device provides shear and torsional resistance and reduces construction time and costs. Additionally, an expanded base design improves the overturning resistance of the tall piers. One-eighth scale single-span shake-table tests were conducted at Southeast University to evaluate the seismic response of this SC tall-pier bridge system. This paper presents a comprehensive overview of these tests, including specimen design, instrumentation, loading protocols, and analysis of experimental results. After the tests, no significant structural damage or residual deformation was observed in the SC tall-pier bridge, demonstrating its excellent postearthquake resilience. Furthermore, due to higher-order effects, the opening displacement at the bottom of the piers exhibited a weaker correlation with the girder lateral displacement. The maximum acceleration response occurred in the central region of the bridge pier. The test results show that the maximum residual displacement of the structure was less than 2 mm during the shake table test, corresponding to a drift ratio of 0.032%. This indicates that the structure has good self-centering ability. Additionally, the energy-dissipating devices effectively reduced structural deformations under seismic action, with a maximum energy dissipation ratio of 44%. These results demonstrate that the design significantly enhances the stability and safety of the structure during an earthquake. This study provides valuable insights into the seismic behavior of the proposed SC tall-pier bridge system for enhancing the resilience of tall-pier bridges in seismic regions.