Seismic Performance Of Square Tubular Column To H-shaped Steel Beam Frame And Shear Behavior Of Diaphragm-through Joint

Concrete-filled steel tube is obtained by filling concrete into steel tube.The concrete-filled steel tube component combines the material advantages and excellent mechanical properties of steel and concrete and produces ‘one plus one greater than two’ effects.The diaphragm-through joint is a common form of joints used in the concrete-filled steel tubular frame structure.At present,there are many researches on the performance of this joint at home and abroad,but there are still few studies on its shear capacity,and the shear failure of the test is not obvious in the test.The actual mechanical behavior of the joint in the frame and the influence of the overall performance of the frame on the failure mode of the node are not considered.Based on experimental research,finite element method and theoretical research,the seismic behavior of the steel tubular column to H-shaped beam frame with the diaphragm through joints and the shear capacity of the joint are studied.(1)Three cruciform square steel tubular column-H-shaped steel beam diaphragmthrough joint specimens were designed to investigate the failure mode and stress-strain distribution characteristics of the joint under low cyclic loading.The load-displacement curve and the skeleton curve obtain the ductility and energy dissipation capacity of the node.Parameters involved are the thickness of the web and the flange in the panel zone and the thickness of the diaphragm.Three frame specimens were designed to investigate the overall seismic performance of the square steel tube to H-shaped steel beam frame and the influence of frame performance on the performance of the joint.In order to obtain different failure modes,parameters are span,column section,whether concrete is filled,and whether the panel zone is weakened.(2)Abaqus was used to establish the cruciform joint specimens and frame specimens,and the accuracy and applicability of the test model were verified by the test results,and further parametric analysis was carried out to analyze the influence of web and flange in the panel zone,the diaphragm thickness and the axial compression ratio on the shear capacity.(3)Based on the frame test,the Abaqus is used to simulate the hysteretic test of the frame,and the parametric analysis is carried out based on the verification;The fullscale frame model is established by using the joint parameters,and the failure mode and the mechanical behavior of the nodes are observed.(4)Combining experimental research and finite element parametric analysis,the shear capacity of the web in the panel zone of the joint and the diaphragm is established.The calculation formula of the shear capacity of the diaphragm-through joint is obtained by linear superposition,and compared with the test specimen and the finite element model to verify its accuracy.