Analysis Of Mechanical Performance Of U-section Steel-encased Concrete Composite Beams

As a new kind of composite beam,U-section steel-encased concrete composite beam has advantages of high bearing capacity, big stiffness and good ductility. Due to these advantages,in recent years it has been paid widely attention and got rapid development in our country. By collecting the exiting research literature at home and abroad, this paper has carried out theoretical analysis of flexural capacity, deflection and shear capacity of U-section steel-encased concrete composite beam through adopting reasonable calculation model and calculation assumption, and the calculation formulas are established.According to the characters of the U-section steel-encased concrete composite beam, this paper sets up its nonlinear finite element model with ANSYS. This model considers material nonlinearity and relative slip between the steel beam and the concrete. The rationality and accuracy of the model is verified by comparing the simulation results with the theoretical results and the exiting experimental results. On this basis, the parametric analysis of cross-section dimensions of the composite beam, material strength and spacing of stud shear connector are carried out to study the influence on the mechanical performance of U-section steel-encased concrete composite beam. The results show that various factors can cause varying degrees of influence on the flexural capacity and deflection of the composite beam.This paper also analyzes the effective flange width of U-section steel-encased concrete composite beam with ANSYS. On the basis of using the static equivalent principle, the parametric analysis of width-span ratio, loading form, thickness of concrete slab, strength of materials and other factors are carried out to study the influence on the effective flange width,and the general rule of the effective flange width varying with load is summarized. The results show that the loading form and the width-span ratio influence the effective width significantly.According to these results, the regressive formulas are suggested.