NUMERICAL ANALYSIS OF THE SEISMIC BEHAVIOR OF A SQUARE CONCRETE-FILLED STEEL TUBE FRAME WITH THROUGH BOLT-END PLATE JOINTS

This study is based on the experimental results of a two-story two-bay composite frame under cyclic loading, built to study the seismic behavior of square concrete-filled steel tube frame with through bolt-end plate joints. The nonlinear numerical analysis was conducted using the finite element software (FES) ABAQUS to analyze the failure mechanism, ductility, energy dissipation and connection behavior of this structure. Before maximum load, reasonable agreement was observed between the analysis results and experimental ones. Considering different parameters, including axial compression ratios, the thickness of end plates, beam stiffeners, and the pre-tension of high strength bolts, the mechanical performance of frames was investigated. The results show that the hysteresis curves of the frame are stable, and the frame has excellent ductility and energy dissipation capacity. The joints have no plastic deformation during the loading procedure. When the axial compression ratio is low, the failure mechanism of frame is acceptable. Increasing the thickness of the end plates and providing beam stiffeners increase the stiffness and ultimate load, and postpone the decrease of stiffness. The pre-tensioning of high strength bolts has no influence on the behavior of frame.