Analysis Safety For Continuous Rigid-Framed Bridge With High-Piers And Long Spans By Finite Element Method

Recently, fast development of the highway transportation system had driven the research and development of bridge structure, the long-term theoretical and practical research had shown that the pre-stressed continuous rigid-framed bridge has a lot of advantages, such as high adaptability, easy building, little investment and high rebound, so it had won wide application and research.As for the long-spanned, pre-stressed continuous rigid-framed bridge with high-piers built in domestic, the maximum height of bridge has been reported as 89m and the maximum height of pier as 81m, while the height of the pier over 60m is fewer reported on abroad. This thesis studies the structural safety of the structure of Yujiang Chongqing No1 bridge with the piers of 88m height. The study of this thesis will provide with scientific basis and promote the development of this kind of bridge Meanwhile, with the development of computer's software and hardware as well as the computational theory, it's possible to analyze the structural safety by finite element method by dividing the local structures and the whole bridge structure. Finite element method can divide the whole structures to finite elements, which can accurately simulate the load mode, deformation and stress distribution. The method is the more accurate and perfect to predict the structural responses.In this thesis, according to the real size of girder-box and pier, the 3D finite element analytical model was set up, considering the various loadings in the period of cantilevered building and normal use, including in deadweight, pre-stress on strand, weight of the hung basket, crosswind, through wind, as well as the worst combine of accidental abnormal loads such as dis-uniform static load, asymmetry building, asymmetry wind load, decentralization construction machinery, material and their dynamic effect, accident earthquake loadings, etc. The author try to find the worst load combination loaded on the structure in order to calculate the displacement, stresses, modes of the bridge, check the structural strength, stiffness, dynamic characteristics and buckling strength of the structure according to the Regulation, ensuring the structural safety. The thesis also discusses about the dynamic character and application capability of the long-spanned continuous rigid-framed bridge with high-piers, analytical method the pre-stress on strand in building, the loading and influence of earthquake on structure and the dangerous load combination in cantilevered building and common use.