Study On Anchor Zone Of Steel-Concrete Composite Pylon Of Cable Stayed Bridge

The span of modern cable-stayed bridges becomes greater than ever before.As the span becomes greater, the pylon becomes higher,this situation brings serious difficulties in design and construction,especially in the conrete casting. On the other side, using the steel pylon with better mechanical performance will requires large amount of additional budget.So it is economical and rational to use the steel-concrete composite pylon in cable-stayed bridge.Generally speaking, pylons of cable-stayed bridge using this kind of structure can be divided into two main styles: steel anchor beam, and steel anchor box.In this thesis, we first introduce the 1:3 segment model experiment of the anchor zone of Guilin-Nanzhou Bridge pylon, which is using the form of the steel anchor beam, and then we use the finite element model to simulate the tensioning procedure and the worst working condition. Thirdly, we describe the experiment procedure and result, compare and analyze the difference between the theoretical value and the experimental value. Finally , we clarify the loading and the transferring method of the cable forces in the anchor zone in the form of steel anchor beam, and conclude some helpful suggestion both for design and construction.In the next section, a plane bar system model is created for each of the two state-of-art forms of steel anchor box. Based on the model, we compute the deformation of the concrete part and the steel part of the pylon anchor zone under the horizontal force of the cable forces, and then use deformation corresponding principle to derive the partition relationship of the horizontal cable forces between the steel part and the concrete part. Then , the corresponding equations are acquired. Further more, we compute the example with the finite element program and analyze the distribution of the cable forces in both horizontal and vertical direction. The veracity of equations are proved through the comparison between the result from equation computation and finite element computation.