Research On Mechanical Behavior Of Diaphragm-through Connection Between CFST Column And H-shaped Steel Beam

Diaphragm-through connection between CFST column and steel beam has been recommended in technical specification for structures with concrete-filled rectangular steel tube members.There is not yet a unified calculation method of bearing capacity of diaphragm-through joints.So the backward research on the bearing capacity of diaphragm-through joints restricts its development and application.Based on the many specially literatures,the development and research advances on the connections between CFST column and H-shaped steel beam are described.The background of this paper is then pointed out and the main contents are put forward.In order to investigate the flexural capacity of diaphragm-through connection,nonlinear finite element analyses of diaphragm-through connections are conducted under tensile loading using ANSYS software.The results indicated that main factors which influenced the flexural capability of joint were thickness of diaphragm and steel tube?axial compression ratio,while the concrete had little effect on the capacity.The yield mechanism had been proposed based on the finite element analysis stress of diagrams of the joints.And through theoretical derivation,the calculation method of flexural capacity was also brought forward.According to the comparison of calculated results of the formula and the experiment results,it can be seen that the tested values and calculated values were in good agreement.In order to investigate the shear bearing capacity of panel zone of T-shaped diaphragm-through connection between CFST column and steel beam,three exterior connection are studied by low frequency cyclic loading test.The failure character and load-displacement curves of panel zone are gained.Based on the core concrete slitting test results,the width of compression strut of core concrete is made clear.The existing calculation methods for shear bearing capacity of panel zone are introduced.Based on the principle of deformation coordination,a calculation method of shear force-deformation skeleton curve for T-shaped diaphragm-through joints is proposed.The theoretical predictions of the method are well fitted with the experimental results.The proposed formula of flexural?shear capacity can provide reference for future research and engineering application.