Research On Static Performance Of The Three-span Composite Beam Cable-stayed Bridge

Bridge is the witness of social progress, society is more prosperous due to the presence of the large span bridges. In recent years, with the construction of China's large span bridge, promote technology innovation the bridge. The emergence of composite beam cable-stayed bridge is the need of large span bridge construction and the social development of bridge construction. Combination girder cable-stayed bridge has small weight, large spanning capacity and superior seismic performance is widely adopted by bridge engineering, which is the trend of the large span bridge construction.Cable-stayed bridge with composite girder constrain relative sliding of the steel and concrete section by shear connectors, improve the flexural carrying capacity of main girder, give full play to the advantages of two kinds of materials of steel and concrete. This paper with the construction of three span, two towers and double cable plane composite beam cable-stayed river bridge in Lanzhou city, Gansu province as the engineering background, research the overall structural performance of composite beam cable-stayed bridge. In the second chapter, this paper analyzes the calculation method of the overall structure performance of composite girder cable-stayed bridge, introduces transformed section method of composite girder cable-stayed bridge, which is used for elastic analysis, shrinkage and creep effect calculation, interacts ordinary stress calculation and shrinkage and creep benefit calculation, introduces the contents of plastic analysis method of composite girder cable-stayed bridge. In the third chapter, the paper describes the basic structure and mechanical characteristics of combined beam cable-stayed bridge, studies the overall structure performance and transfer mechanism of composite beam cable-stayed bridge, the river bridge as a model to propose numerical modeling method based on force transmission of composite beam cable-stayed bridge. The fourth chapter studies that the shrinkage and creep of concrete bridge deck has effect on main binding the internal forces of composite beam cable-stayed bridge, uses the finite element program MIDAS/civil to establish models which considers the refined finite element model of shrinkage and creep effect and does not consider the finite element model of shrinkage and creep conversion section. Deformation and internal force is simulated during the construction stage and completion stage, then analyzes the concrete bridge deck shrinkage and creep which impact of main girder displacement and internal forces of composite beam cable-stayed bridge, and draw quantitative conclusions to confirm the validity of the transformed section method to calculate the shrinkage and creep effects. In the fifth chapter, this paper uses ANSYS / workbench to establish binding girder beam segment model, analyses the main girder shear lag effect of maximum cantilever length of composite beam cable-stayed bridge in construction stage, expounds transfer regularity of main girder shear lag effect, Studies the influence of the shear lag effect to integral structure performance in construction stage of composite beam cable-stayed bridge, proposes measures to ensure the combined beam structural safety in the construction phase of the cantilever beam assembly.