Abstract:
In view of the decreasing trend of column widths in steel residential buildings, a new type of concrete filled rectangular steel tubular column-H-section steel beam connections with external stiffeners is proposed. The diaphragm is removed in this connection. Pseudo-static tests of seven new joint specimens were carried out. The test parameters were the section of the steel beam and the thickness and the height of the long side of the external stiffeners. The failure modes, hysteretic curves, skeleton curves, strength, stiffness degradation, strength degradation, ductility and energy dissipation capacity of the joints were studied. The test results show that there were three failure modes of this new joint, namely, tensile failure of beam flange, weld failure between beam flange and external stiffener, and column wall failure near the external stiffener. The ductility coefficient was 2.17 to 3.67, the equivalent viscous damping coefficient was 0.2 to 0.3, and the average drift ratio was 1/49. The seismic performance of the joint met the requirements of "strong joints and weak members". Increasing the thickness or the height of the long side of the external stiffeners can increase the strengths of the joints. The premature cracking of the beam flange, the welding seam between beam flange and external stiffener, or the column wall will reduce the ductility and energy dissipation capacity of the joints. It is proposed that the connection coefficient should be 1.4 when checking the ultimate strength of the column wall and joint weld. The strengthening or weakening measures on the flange at the beam ends can be taken to ensure that the new joints have a sufficient plastic deformation capacity.