Construction Monitoring And Relative Parameter Analysis Of Cangxi Extra-Large Bridge

With the process of Western Development in China speeded up, more and more bridges needs to cross great rivers and deep grooves in west mountain areas. Prestressed concrete continuous rigid frame bridge is more prefered by engineers because of its long-span ability, convenient and fast construction, lightful line type. Nowadays, the prestressed concrete continuous rigid frame bridge often adopts the cantilever construction technique. This method will result in complex change of the internal forces and displacements in the construction stage of bridge. It is necessary to execute construction control in bridge's construction stage, for the assurance of quality and safety in construction, ensuring the internal force and alignment of bridge meet with the design expectations at the maximum extent.In this thesis, the construction monitoring project of Cangxi Jialing River Bridge is used as an example of engineering practice. By using the finite element software Midas/Civil to simulate the construction process of this bridge, the author obtained the internal force and deformation of each construction stage, provided a full set of data for the construction controlling of Cangxi Jialing River Bridge.First, the main contents including deformation monitoring and stress monitoring of construction monitoring of Cangxi Jialing Rever Bridge are summarized. The problem in camber setting and template elevation determination are discussed, as well as the current problems in stress monitoring.Then by the introduction of construction controlling theory and comparison of analysis methods, the author decided to use the forward-calculation method to simulate the construction stage of this bridge. With parametric sensitivity analysis we can conclude that the self-weight of structure, tension control stress coefficient, pipe roughness coefficient, pipe deviation coefficient, temperature, ambient humidity are the major parameters.At last, the mechanism of concrete shrinkage and creep is discussed, three predict-model of concrete creep and shrinkage which are widely applied nowadays are used in the analysis of Cangxi Jialing River Bridge. The difference of long-term deflection and stress are compared. It is concluded that using the predict-model recommended by JTGD62-2004 Code is more safe than other models, especially in the condition that there is no exact data for application.