| In recent years, curved box girder is applied more and more in the construction of expressway and viaduct for its economy, fine figuration and practicality. However, people meet with a lot of difficulties. The complexity of curved box girder bridge lies not only in its mechanical features but also in other fields, compared with straight one.In order to solve the spatial analysis problem of curved box girder bridge effectively, a static finite element analysis program is presented, in which the box girder is simplified as a grid beam structure to get its internal forces and displacements under dead load and live load. Furthermore, this Visual C++ program, with which two examples are analyzed and some beneficial conclusions are arrived, takes advantage of object-oriented technique.Firstly, the formula are derived for calculating the element stiffness matrix and equivalent node force matrix and the problem of calculating the equivalent stiffness of both lengthways and transverse grid beam is discussed. Those two factors are the base of the program.Secondly, in order to calculate the effect due to prestressing tendons, a method to calculate all kinds of prestressing force losses and equivalent load of prestressing tendons is introduced in detail in this paper, which proves to be advantageous for programming.Thirdly, a simplified method, with which the effect of live load is calculated according to "influence line", is presented in this paper based on the principle of Dynamic Programming.Finally, object-oriented programming is adopted in this paper to build all kinds of program modules, which carry out some specific function and may be used alone or combined with others. The correctness and accuracy of the method and the program presented in this paper are proved by the result of a model bridge experiment. Additionally, the difference of total effect and secondary forces due to prestressing tendons under two kinds of boundary conditions is given.
|
PDF Full Text Request