Construction Control For Large-Span Prestressed Concrete Continous Girder Bridges

The inner forces and configurations of bridges are closely related to the construction methods and process. The inner forces and configurations of large-span prestressed concrete continuous bridge using the cantilever construction method may deviate from the design values due to the following factors, such as non-homogeneity of concrte, properties, variation of geometric parameters, temperature, humidity and time etc. In order to ensure construction quality and construction of bridge structures must be the whole process of strict construction control. With the increase in span of bridges, construction of sub-cantilever structure analysis and control problem is also increasingly becoming a design and construction of the key questions and has drawn greater attention. Bridge construction control means in the construction phases by measuring the key parameters to identify the structure of status parameters, the actual structure of the estimated prediction status, optimal control bridge status. To ensure the construction quality are the key to the projects, the purpose of construction monitoring is to ensure bridge structures sectional stress distribution, deflection can change in security within the scope of reasonable during the course of construction. In particular the main purpose is to ensure that the bridge successfully closed, and the actual elevation deviation from design values of two cantilever ends are not more than the value of monitoring permit. Configurations after the bridge closure are well, and inner forces of structure are reasonable.The present thesis relies on a large-span prestressed concrete continuous girder bridge projects, for large-span prestressed concrete continuous girder bridge construction control of some key issues, such as configuration control, cross-sectional stress are calculated and measured in field. The thesis has the main contents as follows:Firstly, large-span prestressed concrete continuous girder bridge construction control literature review and the main research contents of the present thesis. Second, large-span prestressed concrete continuous girder bridge construction control basic theory. Third, large-span prestressed concrete continuous girder bridge structural finite element analysis. Forth, configuration control of large-span prestressed concrete continuous girder bridge. Finally, test and analysis of sectional stress of large-span prestressed concrete continuous box girder bridge.The main conclusions of this research work are as follows, First, as a result of there are many kinds of uncertainties in the construction of large-span prestressed concrete continuous girder bridges, it is necessary to conduct construction monitoring and control. Second, by comprehensive comparison the results given by MIDAS, GQJS and Design Institute, we can see that the trends of the three pre-cambers are same, and the key points' stress value and inner forces of the control sections are closely. Third, calculation results of bridge configuration are in good agreement with the measurement of bridge configuration, indicating that construction control is achieve the desired results. Forth, during every construction stage, the stress values calculated of key points of the control sections of beam are in good agreement with the tests. After the completion of system conversion and the second dead load, the stress of lower edge of sections of side span and main span have a greater reserves, and the stress distribution of main girder are reasonable.