Finite Element Analysis Of Closed Rectangular Steel-reinforced Concrete And The Calculation Of Ultimate-carrying Capacity Considered The Constraints

Steel Reinforced Concrete structure has been widely used in the field of engineering with its own advantage, it take full performance advantages of the steel and concrete material, and it has more excellent performance on strength, stiffness, ductility and energy dissipation compared with steel structure and reinforced concrete structure. Therefore it becomes more widely used in large span structures and high-rise buildings. Under the action of earthquake, the components tend to be suffering the effect of torsion. However, the study of steel reinforced concrete structure under torsion is still lagging behind other forms of structures and engineering projects, based on the above situation, by experiment and analysis of 14 components through finite element numerical simulation analysis, this paper carried out the following aspects of the research on the closed rectangular steel reinforced concrete under monotonic torsion:(1) By using ABAQUS finite element software simulate the steel reinforced concrete members under torsion that has been tested in the previous literature, and compared with the results of numerical analysis and experimental results, they showed good congruency. It suggests that ABAQUS simulates the applicability of the torsion behavior of steel reinforced concrete very well. And it also suggests that the selected parameters in the process of building models(including the constitutive relation of concrete and steel, material properties, boundary conditions, load mode, etc) are appropriate. They can reflect the actual component characteristics and loading process accurately and lay a foundation for the next step which is the performance analysis of the steel reinforced concrete under the pure torsion effect.(2) Through ABAQUS numerical simulation of the 13 roots of steel reinforced concrete and a root of ordinary reinforced concrete in a state of pure torsion, it got the load-displacement curve and the stress nephogram of concrete and steel. According to them, people analyzed each member’s stress process and working mechanism. People analyzed that the main influence factors(including steel reinforced, the range of constraints, the change of longitudinal steel, the change of stirrups, etc) affect the bearing capacity of torsion. People analyzed the error between the theoretical calculated value of the bearing capacity of steel reinforced concrete members under torsion and the finite element results, and analyzed the causes of error. People verified the expand superposition method for the applicability and accuracy of the bearing capacity of steel reinforced concrete under torsion and found that the range of constraints of steel reinforced had a great influence on the error of the calculation results of the expand superposition method.(3) Based on the variable-angle spatial truss model and the superposition principle, it was first established that the ultimate bearing torsion capacity formula of the closed rectangular steel reinforced concrete member in which there was influence coefficient f introduced, and it provided basis and reference for design of torsion members of steel reinforced concrete in the future.