Stress Analyses Of Anchorage Zone At Cable-pylon Connection And Lower Pylon Legs

Concrete pylon, in most case, have a box cross-section. With cable-stayed bridge span increase, the anchorage zones get larger and larger cable forces. Due to intensity of the axial forces, the anchorage zones have large wall thickness. In addition, because of weaken factors from opening hole, the strength state at this area is very complicated. To decrease the cable forces, the large tonnage and small radius prestressing tendons is needed. But in modern multi-cable stay bridges, some of these bridges have crack and concrete flake away at the anchorage zones. Therefore, more study on stress distribution at the anchorage zones is needed.At the same time, the lower tower not only withstanding formidable cable force, moreover withstands the tower column's under dead load, has the obvious stress concentration spot, needs to analysis the stress distribution.It is important to know the stress distribution of anchorage zones and lower tower well. Not only the model test is a useful method to deal with this problem, but also the finite element method is important to do with it before the model test. The finite element method is able to improve the model test and makes up the deficiency of it. Based on a typical single tower cable-stayed bridge, this thesis analyses the stress distribution of anchorage zones and lower tower using the finite element software ANSYS. During the prestressing stage, prestressed tendons converged at the anchorage zone where the stress distributed complicatedly. The study of this paper focuses on the following four aspects in light of the problems:1. Construct a three dimensional space finite element analysis model for the part which is most unfavorable for the anchorage zone of cable support tower.2. The stress distribution of cable-pylon anchorage under annular-prestressing tendon is analyzed.3. The stress distribution of cable-pylon anchorage under cable force and annular-prestressing tendon is analyzed.4. The model simulation of lower tower is presented, and analyse the stress distribution.