Research On Monitoring And Control Technology Of Cantilever Construction For (48+80+80+48)m Continuous Beam Bridge

With the vigorous development of the transportation industry in our country,prestressed concrete continuous girder bridge is widely used because of its advantages of low cost, strong adaptability and good overall performance. Prestressed concrete continuous girder bridge usually adopts cantilever construction method. The method can shorten the construction period, but also make the change of the displacement and stress more complex. In order to ensure that the bridge alignment and stress can meet the design requirements and that the construction can be safe,bridge construction monitoring is necessary.This paper firstly introduces the development status of domestic and foreign construction control, and expounds the contents and methods of construction control of cantilever. Combined with practical engineering, finite element analysis model is established by using Midas/Civil. This article simulates the continuous girder bridge construction process, and analyzes the deflection and stress of each construction stage.By means of finite element analytic model, the sensitivity of parameters which influences the behavior of bridge structure is analyzed. Finally the concrete density and elastic modulus of concrete are identified as the main parameters. From the aspect of linear and stress and internal forces, the effect of changing the bridge closure scheme is analyzed. Based on the closure scheme that the side span is closured firstly, the influence of different moment of removing temporary supports on the secondary interior force caused by prestressing is researched. In the thesis, the best time to remove temporary supports is also explored. The construction monitoring scheme of the continuous girder bridge is established. Based on the scheme, the height measuring points are arranged, and the sensors are embedded in the concrete.The elevation and stress data is measured in each construction stage. It is compared with theoretical data from finite element analysis. The thesis uses the method of least square theory to discern parameters. The thesis analyzes errors and adjusts next elevation of formwork. Finally favorable monitoring effect is obtained.