Analysis And Test On Cable-Pylon Anchorage Zone Of Yongjiang Super-Large Bridge

The anchorage zone of the pylon is a key part for cable-stayed bridges, where the concentrated force of cable will be transferred to the pylon safely and uniformly. Because of the anchorage zone of the pylon bear concentrated forces and have complicated structure, which is key to structural design and construction of cable-stayed bridges.Analysis of strength performance at this area has been attracted attention in bridge engineering all the time.The thesis is based on the construction-in-progress Yongjiang River super-large bridge in expressway, the bridge is a jointed pylon cable-stayed bridge with four cable planes and two cable tower.The tower is without upper cross beam and the tower is connected in the top by concrete slab to form single box with three cell section.Under the action of cable forces and prestress, the mechanical conditions in the cable anchorage zone is extremely complex.This thesis sets out to make brief introduction of the full-scale model test and test result of the anchorage zone of the pylon. Theoretical analysis and full-scale model test are carried out to research the application of circular prestressing system with small radius and the test condition is completely same as the actual construction craft.Through determining the stress loss for the prestressing tendon with great tonnage and small radius, the characteristic of the system in estimation of prestressing loss is analyzed by theoretical method, and the reason that the dispersion of data is large and test results are not consistent are pointed, giving the the frictional coefficientμand the deviation coefficient k value for plastic corrugated pipe and steel pipe.Proposed the guidance for the construction craft of low retracting anchorage,simultaneously enrich and perfect the correlation analysis on theories and the experimental study.Adopting ANSYS10.0 system to carry out detailed finite-element analysis for the anchorage zone of the pylon and comparing it with the model test value.The finite element spatial analysis and the actual test result of full-scale model are basically tallies.The model anti-crack safety coefficient are bigger than 1.65, the anchorage zone of the pylon are safely and reliable.Besides find control point on the section of pylon and put forward the calculation equation for the optimization of prestressed tendon layout and the optimization result is gotten through the equation.The calculation indicates that stress can be more homogeneous by adopting optimized project of prestressed tendon layout, and the optimized project can save prestress materials.