| The steel tube confined steel reinforced concrete structure is a new type of composite structure,which is widely concerned for its high bearing capacity and good ductility,and superior seismic performance and has attracted widespread attention.However,at present,domestic and foreign scholars mainly study the axial compression performance and seismic performance of the new structural column,and they have not systematically studied the external stiffening ring-type steel tube constrained steel-concrete joints of the floor slab.Especially when considering floor slabs,concrete floor slabs in the elastic stage of joint bearing can obviously increase the bearing capacity of joints,which is helpful to study the application and promotion of this joint in actual engineering.In this paper,a kind of outer reinforced ring steel beam-circular steel tube confined steel concrete column joints with RC slab,and the seismic performance of the joint is studied.The specific work is as follows:(1)Use finite element software to establish two three-dimensional models of test nodes that have been done in the early stage.The test and numerical simulation are in good agreement,and the correctness of the parameter selection and modeling method of the model is verified.On this basis,two finite element models of steel-concrete column joints with externally stiffening ring-shaped steel beams and circular steel tubes with floor slabs were established,and the seismic performance analysis of the horizontal displacement and axial compression of the column tops was carried out.The results showed that: The overall performance difference of foundation specimens is small,and the new joints after considering the floor slab have high strength and excellent seismic performance.(2)Analyze the variable parameters of two types of basic joints,respectively study the beam-to-column stiffness ratio,axial compression ratio,floor concrete thickness,strength and reinforcement ratio and other parameters on the force performance,failure mode and seismic performance of the joint in combination with the analysis results,recommendations for parameter values are proposed.(3)Based on the research results of the foundation joints,a restoring force model of the external stiffening ring steel beam-circular steel tube constrained steel concrete column joint with a floor slab was established.The skeleton curve model data and hysteresis law were derived,and the restoring force model of the outlet joint was simplified.The model intuitively reflects its seismic performance and provides a basis for subsequent structural seismic analysis.(4)Integrate the data of parameter analysis in Chapter 3,and fit the calculation formula of the bearing capacity of the node by the influence law of each parameter.The comparison between the fitting results and the finite element results shows that the error range is within10%,which verifies the applicability of the formula and provides a reference for further research and application of this node. |
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