Design And Analysis Of Bearing Capacity Of High Strength Concrete Filled Steel Tube

High strength concrete has a lot of advantages such as low porosity, high density,and high compressive strength. However, as the increasing of strength of high strengthconcrete, the brittleness increases rapidly. How to overcome the brittleness of highstrength concrete and make maximum use of the advantages of high strength concreteare important problems that need to be solved. This paper presents a high strengthconcrete filled steel tubular structure which avoids the disadvantages caused bybrittleness of high strength concrete, and makes the best of the advantages of highstrength concrete. Prestressed concrete cylinder pipe is a special hollow steel tubestructure which makes the maximum use of the advantages of high strength concrete,and it is used to convey fluid.A lot of experimental researches have been done on high strength concreteconstitutive relation and complete constitutive relation of high strength concrete underaxial compression has been presented. Static behavior of high strength concrete filledsteel tube has been studied by many experiments, but the unified theory design formulasof high strength concrete filled steel tube have not been given. Dynamic behavior andductility factor computing method of high strength concrete filled steel tube have notbeen studied enough. Many scholars have studied prestressed concrete cylinder pipe,but most of the computing methods are based on the elastic system design criteria,theory about the plastic bending moment redistribution has not been given. The majorstudies of this paper are as followed.By using the stress-strain relationship of high strength concrete given by this paper,the model of high strength concrete filled steel tubular is built through ABAQUS. Thefinite element simulation results and experimental results are in good agreement whichproves the correctness and feasibility of the model. It also proves the correctness of thestress-strain relationship and parameters used in this finite element model. Staticbearing capacity of concrete filled steel tube is only related to the peak stress ofconcrete, so this paper assumes that the static design theory of high strength concretesteel tube is the same as that of ordinary concrete filled steel tube. This paper use staticbearing capacity formulas of ordinary concrete filled steel tube to calculate axialcompression short column, axial compression long column and bending components,the finite element simulation results, experimental results and formula-calculated resultsare in good agreement.According to the numerical analysis method and limit equilibrium theory, bending member hysteretic performance analysis of high strength concrete steel tube has beendone. The skeleton curve model of bending component load-displacement curve ofordinary concrete filled steel tube are adjusted, and the displacement ductilitycoefficient of high strength concrete bending members steel tube is calculated.Types of loads of underground pipe are systematically introduced in this paper, andthe calculation methods and formulas of the main load are presented. This paper alsogives the tube section axial force and bending moment calculation method underinternal pressure and loads. By controlling the ultimate axial force and the ultimatemoment, plastic moment redistribution method of prestressed high strength concretefilled steel tubular pipeline structure is presented. The correctness and feasibility of thetheory are validated by example calculations and finite element simulations.