Based on the low cyclic loading test results of vertical stiffener joints between concrete-filled double steel tubular (CFDST)\ncolumns and steel beams, the shear transfer mechanism and shear resistance were analyzed in this paper. A conceptual model\nformulated was presented in terms of equilibrium and stress-strain relationships. The results calculated by the theoretical model\nand the available experimental data were compared, and then one new concept of shear storage coefficient was proposed for the\ndetermination of the shear storage capacity of the joint, which quantitatively explained the ductility failure progression of the joint\nspecimens in the seismic performance test. It was concluded that the vertical stiffener joint had sufficient shear resistance, which\nmet the seismic design principle of strong shear and weak bending. Results show that the ribbed joints have greater shear\nresistance than unribbed ones; lengthening the overhang of the vertical stiffener can both increase shear resistance and shear\nstorage capacity of the joint; axial compression ratio can reduce the shear storage capacity. The paper also suggests that the joint\ndesign should ensure enough safety storage of shear resistance to improve the seismic performance.
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