DEFORMATION ANALYSIS MODEL AND VALIDATION FOR PRECAST SEGMENTAL CONCRETE FILED STEEL TUBE SELF-CENTERING BRIDGE COLUMN

To improve the resilience performance of prefabricated bridge structural system in medium and high seismic hazard areas, prefabricated assembled concrete-filled steel tube (CFST) with internal energy-dissipating steel bars is proposed. The basic mechanical properties are explained. Then, the simplified non-iterative deformation analysis method is proposed based on the "diagrammatic multiplication method" and "modified monolithic beam analogy method" for design, and special considerations are focused on the treatments of the deformations (flexural deformation, shear deformation and joint rotation), nonlinear behavior (decompression status, equivalent yield status and recoverable design limit status), and strain penetration effect due to strain differences between the steel and the concrete members. For validation, a quasi-static test result, a proposed iterative analysis algorithm and a fiber-based FEA model on OpenSees platform are adopted. The results show that the proposed model can accurately predict the load-deformation relationship and the skeleton curve of the prefabricated CFST self-recentering column. The errors between proposed model and quasi-static test results for the decompression bearing capacity, the equivalent yield bearing capacity and the recoverable ultimate bearing capacity are 7.02%, 6.38% and 11.06%, respectively. This method provides reference for innovative structural design.