Research on damage of specially shaped CFST column-steel beam joints

This paper studied the damage evolution of specially shaped concrete-filled steel tube (CFST) column-steel beam joints subjected to cyclic loading. Six specimens were constructed, comprising three edge joints with T-shaped columns, two corner joints with L-shaped columns, and one interior joint with cross-shaped columns. The failure patterns, force-displacement curves, energy dissipation capacity, and cyclic strength degradation were examined. The experimental findings indicate that the failure patterns of the specimens are mainly the shear failure in the joint core area. The hysteretic curves of the joints are plump, with an equivalent viscous damping coefficient ranging from 0.234 to 0.291. The displacement ductility coefficient of the joints is 1.65-2.36. Utilizing the ParkAng damage model, the damage index of the joints at the characteristic points were calculated and the influence of critical parameters on damage evolution was analyzed. Additionally, the proportion of damage attributed to the accumulative energy dissipation and inelastic deformation was also analyzed.