Seismic performance of the joint between unequal-depth steel beam and CFDST column

Combining the characteristics of concrete-filled double-skin steel tube (CFDST), this paper devised a joint construction form featuring low-beam with haunch partially penetrating into the inner layer of steel tube, thus proposing the joint between unequal-depth steel beam with haunch and CFDST column. This paper conducted finite element analysis of this novel joint under low-cycle reversed loading using ABAQUS software. By taking beam height ratio, axial compression ratio, beam-column width ratio, beam flange width-thickness ratio, and beam web height-width ratios as analysis parameters, the seismic performance of the joint was systematically studied. The results indicated that beam height ratio, axial compression ratio, beam-column width ratio, and beam flange width-thickness ratio have a significant impact on the seismic performance of the joint, while the beam web height -width ratios has a minor effect. Furthermore, through the analysis of the force mechanism and internal force derivation of the core area of the joint between unequal-depth steel beam with haunch and CFDST column, a shear bearing capacity calculation method applicable to such connections was established. This calculation method aligns well with the numerical analysis results and can accurately assess the shear bearing capacity of the core area of this type of joints.