Research on seismic behavior of cruciform special-shaped CFST column to H-section steel beam joint

To investigate the seismic behavior and failure mechanism of interior joint between concrete-filled steel tubular (CFST) column and H-section steel beam, quasi-static tests were carried out on six specimens with scale ratio of 1∶2. The damage process and failure mode were observed, and the load-displacement hysteretic curves, the joint shear deformation, inter-story drift ratio composition, energy dissipation capacity and strain distribution were analyzed. A finite element (FE) model using ABAQUS software was established and verified with the experimental results. Furthermore, a parametric analysis with the FE model was conducted to investigate the influences on the joint shear capacity and joint stiffness. The results show that the hysteretic curve of the joint is plump. The ductility coefficient is between 2.63-4.45. The equivalent viscous damping coefficient is between 0.202-0.241. The deformation and energy dissipation capacity of the joint panel zone are relatively favorable. The finite element analysis model can be used to simulate the seismic performance of the joint. Numerical results show that increasing the joint steel tube thickness can significantly improve the shear resistance of the joint panel zone, and increasing the vertical rib dimensions can effectively improve the joint stiffness. To meet the rigid joint requirements of vertical rib joints, it is suggested that the width thickness ratio of column steel plate should not be greater than 30. The outer height of the vertical rib, the inner height, the connection length between the vertical rib and the beam flange should not be less than 30%, 15% and 150% of the beam flange width, respectively. The thickness of the vertical rib should not be less than the thickness of the beam flange.