Dynamic Performance Analysis Of Steel Recycled Aggregate Concrete Filled Steel Tube Column To Composite Beam Joints

Traditional building industry,a large number of mining sand and gravel and other nonrenewable natural resources,at the same time consume large amounts of energy and bring a lot of construction waste,in order to solve the problem of the construction waste pile up and reuse the non-biodegradable,improve people’s perception for the construction industry,as always,this research conducted on recycled concrete research.For recycled concrete caused by the initial damage of low bearing capacity,ductility,steel pipe constraint steel column with high bearing capacity,and through the cut out the operation of the pipe to avoid the problem of the local buckling of steel tube column,also use the constraint function of steel to improve the effect of the steel tube to concrete constraints,makes concrete can give full play to its performance.My research group has carried out in-depth development on the new type of joints of steel recycled aggregate concrete filled steel tube column to composite beam,intends to study the node form can give full play to the advantages of both,to achieve the "1+1>2" combination effect.The main research results are as follows.（1）By reading the literature of domestic and foreign scholars on steel tube confined（recycled）concrete column and steel tube（confined）concrete column-beam joint,the research status of the above two structures is summarized,and on this basis,a new type of beam-column joint form is proposed for this topic.（2）Refer to the testing model is put forward in the paper,using nonlinear finite element simulation technology,recover 1:1 simulation analysis was carried out on the model,through the failure pattern,hysteresis curves,skeleton curves of three aspects: contrast,verify the veracity and reliability of the simulation model,build this topic proposed the node model for subsequent laid a solid foundation.（3）On the basis of model verification,for the new beam-column joint structure proposed in this project,four sample models were established respectively from two aspects of space mid-column joint and plane mid-column joint,and whether there is a floor or not,and the nonlinear finite element analysis was carried out on them.The simulation results were studied from the failure mode,hysteresis curve,skeleton curve,bearing capacity,stiffness degradation,energy dissipation capacity,ductility analysis and other aspects.The research results show that the joint structure proposed in this project is reliable,the beam end failure occurred in all the specimens,and the column body and the joint constraint area can be kept intact when the failure occurs.Compared with the plane mid-column joints,the spatial midcolumn joints have higher bearing capacity and superior energy dissipation capacity through the configuration of cross-beam.Due to the cracking of floor concrete,the specimen with floor slab is forced to enter the yield stage in advance.Meanwhile,due to the rapid development of floor concrete damage,the stiffness degradation of the whole specimen develops rapidly.（4）For the node with floor space in the column,set up a total of 28 specimens on 6 kinds of parameter model,respectively from the seismic indicators analysis of various parameters for the node form of energy dissipation effect,the results show that because of the core node has superior shear capacity,each specimen beam end failure,displacement ductility coefficients can be greater than 3.0,belong to the better ductility specimen.All the specimens can meet the requirements of the displacement Angle between yield layers and the displacement Angle between failure layers in the code,showing excellent energy dissipation capacity.The parameters that have obvious influence on energy dissipation of joints are axial compression ratio,beam-column rigidity ratio and floor thickness.（5）On the basis of the existing restorative force model,a restorative force model for the new joint proposed in this topic is put forward,which can provide a reliable theoretical basis for the subsequent elastoplastic second-order analysis.In this model,a specimen is selected from the six parameters in Chapter 4 respectively from the two aspects of skeleton curve and hysteretic curve for verification.The verification results show that the proposed restoring force model can truly reflect the actual energy dissipation performance of the test,and can effectively reflect the influence of various parameters.