Finite Element Analysis Of Seismic Behavior Of Composite Joint Of Concrete-filled Steel Tubular Column-Reinforced Concrete Beams

Composite joint of concrete-filled steel tubular(CFST) column – reinforced concrete(RC) beams is a hub of frame structure connecting structural members and transferring forces. Because the force and deformation of the joints under seismic load play an important role during earthquake, it is necessary to investigate the mechanical behavior of the composite joint of CFST column- RC beams under low cyclic loading.This paper uses the finite element software ABAQUS to establish the finite element models of two types of joints and conducts nonlinear analysis on these joints under cyclic loading. Numerical analysis results are compared with the experimental results to verify the effectiveness of the models. After that, this paper further investigates the effects of strength of the concrete in steel tubes, thickness of steel tubes, stirrup and axial compression ratios on the hysteretic performance of these joints through parametric analysis; it provides a reference for the design of the composite joint of CFST column- RC beams.The analysis results show that the finite element results coincide with experimental results on failure modes, the development of the cracks and the P-? curves under cyclic loading. These agreements show that the models are effective to model the behavior of these joints.Parametric study shows that basic strength of the concrete in steel tubes will not increase bearing capacity and rigidity of these joints, but it will increase the seismic behavior of these joints. Thickness of steel tube will significantly increase bearing capacity of these joints. When stirrup increases, bearing capacity and rigidity of these joints will increase. Axial compression ratio will hardly increase bearing capacity of the T-shaped joint, but it will increase bearing capacity of the cross-shaped joint within a certain range.