Research On Mechanical Properties And Section Parameters Optimum Of Prestressed Steel & Concrete Composite Box Girder

In the modern bridge engineering, after reinforced concrete structure, pre-stressed concrete structure, steel structure as well as bricks and stones concrete structure, the Steel & Concrete Composite Beam become the fifth structure.Compared with the steel structure ,the Steel & Concrete Composite Beam may save the steel quantity and enhance the durable and so on。Compared with the concrete structure it may reduce the dead weight and the structure size greatly. It also convenience for the construction. But until now, the domestic and foreign scholars made less research in the Prestressed Steel & Concrete Composite Box Girder. domestic present standard does not have the explicit stipulation to its section parameter's value, this serious influence Prestressed Steel & Concrete Composite Box Girder's research and the development.This article take the Star Light bridge in the Mongolian provincial road 216 as a background, the mechanical properties of prestressed steel & concrete composite box girder has been carried on the analysis. On the basis of structure optimum design idea, section parameter optimum theoretical model is founded, section design variable optimum value confines corresponding variable parameter are obtained through analysis by Matlab.1.By researching the resisting moment,resisting shear,resisting torsion,local stability and conjunction piece of prestressed steel & concrete composite box girder,a series of restraint equations which met character restraint condition of resisting moment, resisting shear, resisting torsion and local stability are deduced.2.Based on the nonlinear optimization theory, section design variable optimum value confines corresponding variable parameter are obtained through analysis by Matlab.Change pattern and sensitivity of box girder section parameters, which named design variables, are analyzed with changes of moment, concrete slab thickness and so on. It has given the relation between the optimized parameter, and has compiled the optimization design procedure.So the design of this kind bridge to be more scientific and more economical.3.To make the mechanical properties contrastive analysis between prestressed steel & concrete composite box girder and steel & concrete composite box girder, by using the large-scale finite element procedure ANSYS.The rigidity contribution of pre-stressed for wo kinds of different structure is analysised as in the different span and different web thickness. It will provide theory support for design and construction of prestressed steel & concrete composite box girder,and solve the key problem of the design,construction,maintenance in the reality engineering, after research of the key technologies of section parameter optimum.The research can also supply the present standard and display its economic efficiency fully.