Study On The Performance Of Joint Between Concrete Filled Square Steel Tube Column And H-Shape Steel Beam

The concrete filled square steel tube (CFSST) column steel frame structures are more and more widely used for the advantages such as more economical, higher strength, better rigidity and seismic performance, short construction period and so on. But there are little theory and test research of the connections between the CFSST columns and H shape steel beams in our county, so it has important theory and application value to research the connections between the CFSST columns and H shape steel beams for the development and application of the CFSST column frames .The research on the joints between the concrete filled square steel tube columns and H shape steel beams mainly focus on the inner diaphragm Joints at present, and the weld steel tube columns are generally used. The seismic performance of outer diaphragm joints and vertical stiffener joints (using cold formed steel tube columns) is researched in this paper based on the Multi-story structures often using cold formed steel tubes.To research the hysteretic behavior, energy dissipation capacity, ductility, the stress distribution and force transfer mechanism of the two kind joins, two outer diaphragm joints and two vertical stiffener joints between the steel tube columns and H shape steel beams are designed and tested under the low cycle reverse loads. The 3D solid finite element models are built by the dimension of the CFSST specimens, and the nonlinear finite element analysis is done using software ANSYS. The results of finite element analysis coincide to the results of the experiments. Then the influence of the breadth of the outer diaphragms and the slope of the beam flanges on the performance of the outer diaphragm joints is discussed by the nonlinear finite element analysis with ten different parameters model under monotonic loading.The tests and the finite element analysis indicate that the two kinds joints have enough carrying capacity, better ductility and energy dissipation behaviors. The moment at beam edge of the outer diaphragm joints is mainly bear by the outer diaphragm. Some of the moment is transformed to the column web and the concrete at the panel zone by the outer diaphragm connected to the column web, the remain is transformed from beam flange to the column flange and the concrete at the panel zone by the inboard diaphragm near the column corner. The moment at beam edge of the vertical stiffener joints is mainly transformed from the beam flange to the vertical stiffeners, and then is transformed to the column web and the concrete at the panel zone ultimately. The plastic hinges of the outer diaphragm and vertical stiffener connections appear on the narrowest section of the variety beam flanges,but the plastic zone length of the joint of the variety beam flanges inside the vertical stiffener is bigger than that of...