Experimental Study On The Performance Of Concrete Filled Steel Tube Beam-column Joints Of New Types

Steel concrete composite structure as an important development direction of structure engineering,the structure and properties of concrete-filled steel tubular column and steel beam joints is very important,but four main forms of the connection of the rectangular concrete-filled steel tubular column to steel beam connections in our country have shortcomings.It is difficult to apply the concrete in the steel pipe to the inner partition joints and the internal welding of the joints,so it is not easy to construct.And in the same position,the inner and outer sides of the tube weld the inner partition plate and the flange of the steel beam,which will cause the steel to produce greater residual stress.The exterior diaphragm connection nodes need a larger horizontal ring plate to ensure the strength of the node,inconvenient layouts in the building at the corner of the interior but also a salient,affect the appearance,flexibility and adaptability of the node form.The vertical stiffener joints avoid the convex appear indoor.The construction and installation are also convenient,but the stiffness of the four directions is different,which affects the performance of the node.Although the diaphragm connecting joints are simple in construction,convenient in constru ction,strong in flexibility and clear in the form of force transmission,the welding of the lower flange weld of the steel beam needs two times of welding,and the weld is prone to be defective.Many scholars at home and abroad are constantly put forward new forms of connections,in order to find the node form more reasonable,this paper studies a lot of literature on learning,innovation proposed two new types of joints,and the seismic performance test and finite element analysis,provide the reference basis for the design of concrete filled tube column with H-beam joints.In this paper,the seismic performance of the joint was studied by a low cycle reciprocating load test on 6 specimens of two new types of joints.The failure and damage characteristics of each specimen were summarized and analyzed through the test.Through the analysis of the experimental data,the stiffness,ductility,energy dissipation capacity and other seismic performance of the node were further understood.The experiment shows that the two kinds of joints show strong ductility and energy dissipation during the test.The plastic hinge of JD2 appears on the flange of the steel beam at the 150 cm of the outer end of the stiffener,and the reinforcing plate plays an effective role in making the plastic hinge move outside.In this paper,in order to study the seismic performance of the connections,six solid finite element models were developed by ABAQUS to analyze the seismic performance of connections.The size of the model in the software is the same as that of the test component.The same loading mode and constraint condition are applied to the model when compared with the experimental results.The simulated results were compared with the actual test results.The simulation results are basically the same as that of the test.However,there are no gaps in the simulation software,and there are quality defects in the weld.Therefore,the hysteresis curves obtained by the simulation are more full.After verifying the correctness of the model,the number of studs and the number and position of the bolts of the JD1 were calculated and analyzed.And the thickness of the reinforcement plates,the length of the stiffening plates and the vertical stiffener were calculated and analyzed.By comparing the hysteretic or skeleton curves of each parameter,the influence of each parameter on the performance of nodes was analyzed.