Mechanical Property Analysis Of Concrete-filled Rectangular Steel Tube K-joints

Truss is a kind of lattice system which is composes of member bars.The chord member is the one that perforates on the nodes,and other member bar is called web member.The steel-tube concrete truss is a kind of lattice structure and it has some points,including pouring concrete into the member bars of the steel tube truss,the web members are empty steel tube and connecting the member bars with the web members.This structure has some advantages,including light,high-strength and large torsional stiffness,and it has been applied extensively in bridge engineering,oceanographic engineering and large public buildings.The area of nodes is the area that has the most complicate stress in the whole structure,whose destruction form has influences on mechanical properties and carrying capacities of the truss structures.Thus,it is very necessary to deep study the mechanical properties of nodes.The writer probes into the research status of the steel-tube concrete nodes at home and aboard,and analyzes the structure characteristics and the mechanical properties of K-shaped nodes of rectangle steel-tube concrete truss through reading large amounts of literature.The main research contents are as below:(1)The three dimensional nonlinear numerical analysis model of K-shaped nodes of rectangle steel-tube concrete is established,which is aimed at the mechanical properties and the failure mechanism of K-shaped nodes of rectangle steel-tube concrete truss and uses the finite element analysis technology.The calculation results matches well with the experimental conclusion,which verifies the rationality of the model.(2)The parameter analysis of K-shaped nodes of rectangle steel-tube concrete,including the influences from the width-to-thickness ratio of member bars,width ratio of member bars and web members,the strength of steel tube and the clearance ratio of nodes to mechanical properties of nodes has been discussed with utilizing nonlinear numerical analysis model of three dimensional finite element,and the reference aimed at engineering design has been discussed.(3)The carrying capacity simplified calculation formula concerning the constraint effect from steel-tube to the core concrete and the influence of the thickness of the steel-tube has been discussed,which is based on the local pressure formula of K-shaped nodes of rectangle steel-tube concrete brought by J.A.Packer.With the utilization of this formula,the carrying capacity of the referenced experimental specimen has been calculated.