| Rectangular concrete-filled tubular (CFT) composite structures have obvious merits, such as high strength, good ductility, better seismic behavior, and convenient construction. The traditional connections types of concrete-filled square tubular column to steel beam mainly include external diaphragms and internal diaphragms in steel tube column, joint patterns are singleness. So in this paper, through column bolted end plate beam-to-column connections for concrete-filled square steel tube was put forward. In this thesis, we accomplish the works as follow:1. A total of 3 quasi-static experimental specimens of through column bolted end plate beam-to-column connections for concrete-filled square steel tube were tested. Three specimens with different axial compression ratios had been tested under low-cyclic reversed loading at the end of column to research the hysteric behavior, the degradations of strength and stiffness, energy dissipation capacity and the failure modes.2. The 3D models of beam-to-column connections by 3D solid elements are founded. And the capacity behavior of connections under the monotonic loading is analyzed. The results of nonlinear FEM analyses can show the stresses distribution in the joints better, so that it provides the possibility to patch up the defects that could not observe in experiments in the details.3. Various factors of the influences of joints capacity behavior can be analyzed such as changing axial compression force ratio and thickness of end-plate.4. The equations of simplified calculation method were presents to estimate the load carrying capacity of the beam-to-column connection according to comparison of theoretic analyses with that of experimental result.The main conclusions of this work are listed below:1. The experimental results demonstrated that all specimens developed plastic hinges at the end of beam and provided exceptional hysteretic behavior, ductility and energy dissipation capacity. And this kind of joint met the requirements of the current code for seismic design of buildings.2. The result from the nonlinear FEM model calculation correct well with that from testing.3. From the analysis, it can be seen that the thickness of end-plate and axial compression force ratio is not the main influenced factor of the through column bolted end plate beam-to-column connection for concrete-filled square steel tube.4. The results from the equations of load carrying capacity simplified calculation match the testing data very well. It means that the equations can be applied in primary design.
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