Research On Mechanical Behavior Of Concrete-filled Square Steel Tubular Column With Internal Partitions And U-section Steel-encased Concrete Composite Beam

The research on the joint of concrete-filled square steel tubular column with internal partitions and U-section steel-encased concrete is very little,The study of the force performance and bearing capacity of the joint is not mature enough.Therefore,it is of great theoretical and engineering value to carry on the research on the joint of internal partitions.In this paper,based on the research of this research group,two new types of nodes are proposed: one is the reinforcement Sleeve interior diaphragms type of joint,the other is reinforcement runs through interior diaphragms type of joint,The new node is simple in construction?easy to accomplish prefabricated assembly?convenient in construction.And the mechanical properties of the two joints were compared and analyzed,the main research work and the results are as follows:Based on the experimental study of this group,the simulation results show that the finite element calculation results are in good agreement with the experimental results.And the finite element calculation results are compared with the experimental results,the two are basically consistent.On the basis of model verification,the nonlinear finite element analysis of two new nodes is carried out,and the failure mode and bearing capacity of nodes are discussed.The internal forces of the joints are investigated,the stress distribution and force transfer mechanism of the two joints are analyzed and compared.Research indicates: The damage of the two joints is similar to that of the two joints,both joints have beam bending damage.The bearing capacity of the two joints under the positive moment is similar,the bearing capacity of the reinforcement Sleeve interior diaphragms type of joint is higher under the action of the negative moment.Reinforcement runs through interior diaphragms type of joint due to the reinforcement through the column wall weakened the wall,Some of the area of the column web and the concrete around the negative moment bars show a significant stress concentration.The reinforcement Sleeve interior diaphragms type of joint due to the existence of the upper partition,node domain coordination deformation ability is better,making the joint domain side of the steel pipe wall and core concrete stress distribution evenly.Through the design of a large number of finite element analysis of the impact of the bearing capacity of many factors to analyze.The influence of the parameters such as the ratio of the height and width of the composite beam?the thickness of the composite beam flange?U-shaped steel beam wall thickness?the longitudinal reinforcement ratio of the flange plate?the thickness of the internal partitions?the column axial pressure ratio on the bearing capacity of the internal partition type joint is studied.Results of the analysis show the ratio of the height and width of the composite beam and the thickness of the composite beam flange have a significant effect on the bearing capacity of the joint.The thickness of the composite beam flange and U-shaped steel beam wall thickness have a certain influence on the bearing capacity of the joint.The axial compression ratio,The thickness of the internal partitions and the column axial pressure ratio are not obvious in a certain range.At last,on the basis of parameter analysis,put forward the design proposal of new joint.