The Creep Effects Analysis Of Prestressed Concrete Rigid-Framed Arch Bridge

The creep property is a basic long-term character of the concrete. Since the late 1940s, people have got a great achievement in the understanding of creep and the research of creeping analytical means based on the accumulation of research testing data and sixty years' of practice. But the estimation and control of the creep of concrete and creep effect on structure is a very complex and tough work. Therefore, in order to reduce the error between calculating result and practice, it's badly required to select a mathematic model of creep coefficient carefully, and to check the results with the construction site test.The Fuzhou Youxizhou Minjiang Bridge is a key part of the third period construction of Fuzhou the Second Ring Road. The bridge is prestressed concrete open spandrel rigid arch bridge. The structure is rare at home and abroad for its complicated techniques. In the construction, there will be five different structure systems, and the bridge was cantilever erected by stages. For this kind of the bridge, it is important that we should ascertain the distortion and secondary force of the structure caused by creep, in order to make the final structure curve and internal force satisfy with the demand of design and use..In this paper, based on the original elastic structure-analysis program, the author selects the mathematic mode of creep coefficient from Chinese highway criterion Specifications for Design of Reinforced Concrete and Prestressed Concrete Highway Bridges and Culverts>(JTJ023-85), and develops an analysis program., it involves creep effects to construction staged with the step-by-step finite element method and the age-adjusted effective modulus method, and the Fuzhou Youxizhou Minjiang Bridge analysis and long-term deformation estimation were made with this program. In order to compare and analyze the results of calculation and practice, the author took part in the real-bridge test on concrete creep when the bridge was on building and finished. Comparing the results of computation with the construction site test, it's proved that the result of calculation and the long-term deformation estimation from the analysis program is credible.Moreover, the essay makes simple analysis on some relevant factors of creep, such as aging coefficient, load age, load, and environmental humidity. And it puts forward some suggestions how to reduce bad effects caused by creep. For the time being, long-term site test of the finished bridge could not be achieved; it is suggested to make long-term site test to get a more accurate estimation.