Study For Mechanical Analysis And Design Computation Method Of Cross Diaphragm In Box Girder

Along with the development of city construction and traffic cause in our country, the amount of city bridge and highway crossroads augments increasingly. Style and conformation of bridges become more advanced and acclimation. Continuous box girder casted in site which has favorable structure performance takes place of simple supported beam in superstructure. And in infrastructure, single column abutment and frame abutment are more and more favorable in design personnel because of their agility of setup position. But setting of these abutments leads to more complex mechanics in cross diaphragm and box girder. Furthermore, in a position to reflect practical condition is not merely demanded in structural analysis, to obtain satisfactory result more quickly and economically is also expected. So in the course of city bridge design, the computational method of cross diaphragm in continuous box girder bridge is required more and more imminently.According to the design and computation of cross diaphragm in the Huadengzhan Bridge, a continuous box girder bridge, on the Changhu Highway in Dongguan City, based on theory of finite element, twice plane frame system finite element analysis is put forward. In advance, plane frame system finite element model of the whole bridge is established and the analysis at different work conditions is carried through. Then plane frame system finite element model of each cross diaphragms is established, and the most unfavorable magnitude of its internal forces such as shear stress, bending moment and so on is picked up. According to the relationship among bending moment, shear stress and distributing load density, equivalent load could be calculated, and equivalent load is applied to plane frame system finite element program. The design and analysis of prestressed cross diaphragm is given subsequently.In order to validate the computational method above, space finite element analysis of the Huadengzhan Bridge through large software ANSYS is adopted. Space finite element model of the whole bridge is established. Coupling of concrete and prestressed steel, boundary condition of pile and soil, system of space bearing, system of abutment and base are simulated, which provide some valuable referential information about establishing space finite element model of bridge constructions in the same style.Finally, the results of two computational methods are generally compared, the applicability and accuracy of twice plane frame system finite element analysis method is verified. Some applicable and recommendable conclusions for design and calculate of cross diapragm in box girder are educed and technical information used for reference in design of city bridge which is planning to be constructed is provided.