Analysis of Stress Influence of Top Deck Thickness on Main Girder with Box Cross Section Used in Cable Stayed Bridge

In the paper, four different finite element models were established based on box girder with different thickness of the top deck (22cm, 30cm, 35cm, and 40cm). In addition, the article analyzed the three-dimensional stresses distribution characteristics of the model and the disadvantages of twin-box single cross hammerhead sections of cable-stayed bridge and stress varying in different thickness of the top deck of cable-stayed bridge were also indicated. In order to consider the affections of the adjacent zone out of the girder section, the internal-forces of two-end surface that were derived by the structure of linear element analysis were exerted on each model respectively. Moreover, the construction load, weight, cable force and pre-stressed force including girder longitudinal, diaphragm transverse and inclined web vertical direction were considered. Based on the above, the three-dimensional stresses of the box girder with different thickness of the top deck of cable-stayed bridge were also analyzed. Finally, from the result of the above working situation, stresses distribution characteristics of twin-box girders of cable-stayed bridge were indicated and the reasonable designs were proposed. Analysis showed that the stress distributions of main girder are reasonable when the top deck thickness is around 22cm.