Simulation Study On The Structural Performance Of Steel-Concrete Composite Box Girder Bridge With Variable Cross-section

With the improvement of road level and the expansion of construction scale, bridges tend to have longer span, more colorful styles, and lighter weight of construction. The development of steel - concrete composite structure provides completely a new idea for the solution of some technical difficulties of bridge project, and becomes important development direction in the inovation of bridge-structures. Since so far China has no design specifications on steel - concrete composite bridges, the study on this area has great practical significance and reference value.Based on the characteristics of bridges with variable cross-section and its common style of variations, this paper analyzes the mechanical characteristic of steel - concrete composite box girders. Then a practical project of a three-span continuous steel - concrete composite box girder bridge with variable cross-section is modeled by using Sap2000 finite element software, and a study is conducted on some problems such as the flexural rigidity, the torsional rigidity, the plates'stresses, the effect of preloading the concrete bridge deck to prestress it, the distribution law of shear studs'internal force under construction load, and the mechanical characteristic under lane load, as well as the precamber of steel - concrete composite box girder bridge, with some useful conclusions summaried.It is found out that as compared with steel-concrete composite box girder bridge with constant cross-section under the construction load, the flexural rigidity and the torsional rigidity of such bridge with variable cross-section have been greatly improved, the plates' stresses are significantly reduced, much better preloading effect by prestressing the concrete deck has been obtained, and the distribution of shear studs'internal force follows certain law. Under the lane load, it has higher flexural rigidity and the torsional rigidity, and smaller longitudinal moment and lateral moment of the deck element. From the calculation and analysis, the suggested coefficient of the shear studs'internal force and precamber were given.