Analytical Method And Program Design Of Camber Prestress Concrete Box Girder

Curved prestressed-concrete box-girder bridge, with its economic, aesthetic and practical features, has been widely adopted in China bridge construction. But because of the complexity in mechanical properties, loadings, structure, construction technology, and other aspects,and easy using in calculating program,many issues are still there to be resolved. The main problem researched in this paper is to workout a friendly finite element program,under the complexity in curved girder bridge analysis,which is using proper calculating theories,to solve a series of the problem in curved girder bridge finite element analyse.In this paper, grillage analogy has been used in finite element analysis on curved beam bridge, three-dimensional straight-lever unit, which has six degrees of freedom for each node, is used to analyse the vertical and horizontal structure of the grillage, element stiffness matrix, coordinate transformation matrix and overall stiffness matrix for straight beam element is derived,the handling of boundary conditions is discussed, and the equivalence load of the prestressing force has been envolved, then the gross effect of prestressed reinforcement and secondary internal force is calculated through equivalent load.To research the value of meshed grid and beam stiffness, the method of confirming the value of meshing grid and beam stiffness when analysising the prestressed concrete box-girder bridge by grillage was educed: while meshing the girder by grillage, when each vertical beam grid components corresponding to the central angle in four to five degrees, if the breakdown of the results of the grid had little impact, the results were convergence. An example used to illustrate the structure of the upper beam cross-section of the grid value.The above-mentioned content is programming under Fortran90 language in Fortran PowerStation4.0 integrated development environment, static analysis module is obtained through straight-lever grillage finite-element method for superstructure of curved beam bridge, Visual Basic 6.0 language is used to programming a friendly interactive input interfaceFinally, the correctness of this theoretical analysis and the accuracy of this program are verified through the calculation example.