Determination Of Rational Completion Status Of Cable-Stayed Bridges By Combined Bending Energy And Stress Balance Method

It is a key problem to determine the reasonable cable forces in designing cable-stayed bridges. Surrounding this subject, many researchers in or outside the country have published many theses. On the basis of analyzing and generalizing the former researchers' achievements, the least bending energy method combined with stress balance method is adopted to determine the reasonable cable forces by using the large-scale general finite element process ANSYS.The least bending energy method takes the bending energy as the objective function, and gets the reasonable cable forces by seeking the least bending energy. The cable forces obtained by using the method are uniform. But in the solving process, the area of towers, girders and cables is magnified artificially. The influence of pre-stress can't be exerted and the potential energy caused by cable is ignored, so cable forces in dense cable area are unreasonable. Using this method can only determine cable forces caused by dead loads, but can't by live loads. The stress balance method aims at the girders' reasonable moment, getting the cable forces by balancing the stress in girder's upper and lower margin. Using this method can consider the influence caused by dead loads and live loads meanwhile. But cable forces in dense cable area are unreasonable. The synthetic method takes the state determined by least bending energy as its initial state, which is the base to adjust cable forces. Then according to the girders' reasonable moment, cable forces are adjusted to get the reasonable forces. Using this method can make good use of the two methods, and the cable forces determined by this method are more reasonable than that of the two.Up to date, when designing the reasonable cable forces of cable-stayed bridges, the special bridges design process is adopted. In this article, based on the large-scale finite element process ANSYS, a bridge's cable forces are calculated by using the least bending energy method, stress balance method and the synthetic method respectively. After comparing the results, it can be shownthat using synthetic method is prior to anyone of the two. The function of the large-scale general finite element process ANSYS is powerful. It can be used conveniently and exploited greatly, so it can be used in determining the reasonable cable forces. If it can be exploited rationally, its calculation accuracy is more credible. In the article, author firstly use large-scale general finite element process ANSYS to calculate rational completion status of cable-stayed bridge with three methods, compare the results and demonstrate the advantages.