Study Of Key Control Technologies During The Process Of Installing The Large Cable-Stayed Bridge’s Upper Pylon

Construction scheme of installing steel upper pylon by the method of integral hoisting is studied for taking advantage of steel bridge tower in bridge engineering and avoiding the defect of the traditional construction method of steel bridge tower,which also focus on solving the practical problem of height restriction of aviation during the construction period.Based on the successful practical experience of bridge tower construction,the research use the Hong kong-Zhuhai-Macao bridge as a case and focus primarily on construction control and calculation during the upper pylon construction period.Using methods such as finite element analysis and contrastive analysis between theoretical calculation and measured data,the main works and achievements are as follows:1、The study of construction control during the process of installing upper pylon by the method of integral hoistingAccording to the construction scheme of installing upper pylon of cable-stayed bridge by the method of integral hoisting,the main control contents of each stage are elaborated and the controlling essentials of structures under different working conditions are ascertained on the stage of temporary storage,attempting lifting and turning upper pylon.According to each controlling essential,the controlling sections and measured points are designated reasonably and the corresponding monitoring plans are made for ensuring the safety and feasibility of the construction.2、Simulation computation analysis of construction controlling essentialsThe spatial finite element model is established and the girder deflection is calculated by the methods of both numerical simulation and hand computation,then the effectiveness of the girder deflection calculation is verified.The displacement change of the temporary pier is calculated after putting the upper pylon on the girder.The force state of steel tube support and the rigid fixity section of pylon and girder are analyzed during the process of installing upper pylon,then the rationality of the structure forced state is proved during the construction of hoisting upper pylon,which lay a solid foundation for successfully implement the hoisting scheme.3、Contrastive study between theoretical calculation and measured data during construction periodThe controlling essentials of structures under different working conditions are monitored and on the stage of temporary storage,attempting lifting and turning upper pylon and the difference between theoretical calculation and measured data is analyzed according to the controlling essentials.The practical engineering is guided by the theoretical calculation,which effectively control the structure forced state during the process of installing upper pylon.The effectiveness of the integral hoisting construction is proved by monitoring the coordinates of pylon after finishing the installation of the upper pylon,which not only has a great significance for perfecting the rationality and the reliability of the pylon construction scheme but also has an important reference for the similar construction of the large cable-stayed bridges’ upper pylon.