Research On Prestress-Loss Of High-Speed Railway Prestressed Concrete Simple Support Box-Girder

With the rapid development of railway in our country, prestressed concrete bridge is required of higher bearing capacity and dynamic performance. In construction of high-speed railway, prestressed concrete simple support box girder is widely used for its unique advantage. In prestressed concrete bridge, the size of prestress-loss effects the size of the effective prestressing force, and then effcts the performance of whole component and even the whole structure. So, prestress-loss have been one of the important subjects for research of the prestressed concrete field of all time. Because the influential factors of prestress-loss are numerous and some factors influence each other, calculating accurately prestress-loss is a very complicated job.Prestress-loss will bring about little effect to the structure strength. However, it will affect the structural performance under loads (e.g., camber, cracking load). Both higher and lower estimate of prestress-loss of the structure is adverse to the structure. Only estimating accurately the prestress-loss of the structure in the construction course and operating course, optimizing design of the prestressed structure, distributing properly the prestressing tendon, and guaranteeing the bearing capacity of the concrete stucture, the security and dependability, economy and service life of the structure can be convinced.In this paper, the prestress-loss in the prestressed concrete structure will completely be analyzed in the theory and several kinds of method of calculation of prestress-loss will be introduced. In this paper, combined with prestressed concrete simple-support box girder of Hefei-Wuhan special passenger line, MIDAS/Civil is used to calculate prestress-loss of the structure. By friction coefficient test on the pipeline at the construction site, the reasonable friction and deviation coefficient can be acquired which offered the basis for a pulling force of rational determination in construction course.Through setting up solid finite element model in ANSYS, the relativity of the result of static and dynamic load testing of bridge ( deflection, mode of vibration, frequency) and prestressing force is analyzed.