Analysis of ultimate seismic performance of thin-walled concrete-filled steel tube bridge piers under dynamic load

This study entailed the use of a cyclic loading test on a thin-walled concrete-filled steel tube (CFST) bridge pier to investigate its ultimate seismic performance. Additionally, a three-dimensional solid-shell finite element (FE) model of thin-walled CFST piers was established using ABAQUS. Cracks were introduced into in-filled concrete, and ductile damage was imposed on the steel tubes, in order to accurately reproduce the seismic performance degradation and post-earthquake residual displacement variation in thin-walled CFST bridge piers. The FE model was validated using pseudo-static and pseudo-dynamic loading tests performed on thin-walled CFST bridge piers. The analysis indicates that the FE model with concrete cracks can reflect the pinching effect of the hysteresis curve; the ductile damage can reflect the degradation of the bearing capacity during large plastic deformation under cyclic loading and the residual displacement under unidirectional and bidirectional dynamic loading. The seismic response of the full in-filled thin-walled CFST bridge pier was the least under the same intensity seismic wave, the in-filled concrete could improve ultimate seismic capacity. Finally, this study established a formula for the relationship between the residual and maximum displacements at the top of thin-walled CFST bridge piers under bidirectional seismic waves.