Research On Construction Control For PC Continuous Rigid Frame Bridges And Analysis Of Creep And Shrinkage Effect

With the development of bridge construction and improvement of prestressed technology, more and more large-span PC rigid frame bridges are built. To keep the accordance of alignment of built bridges with the expection and to insure the safety in bridges construction, the construction control is paid more and more attention. To built bridges, the persistent long-term deflection in the middle of the span becomes a familiar problem. In the dissertation, by engineering practice assisted with theory analysis, on the basic of the contraction of Nanhe Bridge constrution, the application of "Adaptive Control" in constrution control of long span PC rigid frame bridges is discussed. Then factors casusing the deflection are analyzed and the methods to reduce deflction are discussed.Main research works of this dissertation are included below:(1)Make a review of development and study about Large-span PC continuous rigid frame bridges in China and abroad,calculation methods of concrete creep and shrinkage and methods of construction control.(2) The mechianics and influncing factors of creep and shrinkage is analysed. The methods of calculation of creep and shrinkage are given a review, the methods of calculation of deflection of continuous rigid frame bridges and prestressed losing are deducted.(3) The theory and system of constrution control are given a review and the method of deflection analysis and adjustment is raised based on the "Adaptive Control" theory.(4) On the basic of the contraction of Nanhe Bridge, with the FEM,the factors which influnce the alignment control of PC continuous rigid frame bridges, such as concrete creep and shrinkage, jacking force, age difference,are analyzed.The application of "Adaptive Control" theory in construction control is discussed. The data of stress measurement is analyzed based on the concrete creep and shrinkage theory.(5) On the basic of the construction of Nanhe Bridge, the factors casusing the Long-term deformation are analysised. The methods to reduce the long-term deformation are put forward and the effects are discussed.