Prediction And Analyse Of The Creep Deformations Of Prestressed Concrete Simply-supported Box Girder In Different Construction Stage

Be due to the construction of concrete box girder is different from continuous beam, theconstruction process has no obvious system transformation, It is generally recognized that theconstruction process of concrete box girder construction stage does not exist in the strictsense,but the construction process of prestressed concrete simply supported box girder is verylong and be due to the creep of concrete the deformation of the beam body will graduallyaccumulation. the control of beam linear is mainly from the three construction nodes that isconcrete pouring, rail board construction and lay railway tracks, and adjust the volume is verylimited. If the box girder ofthe linear control is undeserved, when the high-speed railwaybridge in operation stage to adjust the alignment is very difficult, it not only relates to thetechnical aspects of theproblem,butalso to pay a high economic cost.The main work of the thesis includes the following contents based on the above reasons.Firstly, Through the research work on the Liu Yuan beam field of the new second-linehigh-speed railway from Lanzhou to Xinjiang. understanding of the precast box girderproduction process in-depthly and collecing the the related research data.Secondly, Understanding and review the theory and analysis method on creep ofconcrete, and provide convenience for the research problem further.Thirdly, Making an elementary analysis aboat the non material factors that is initialcurvature of the beam body (camber) and box girder sections of different components of thecross section area influencing the creep of concrete.Then, The32m high-speed railway simply-supported box girder as an example, usingbeam theory and finite element method and the different creep prediction model of box girderto forecasting analysis the creep deformation with different construction stages.Finally, After analysising the creep deformation of the construction stage aboat boxgirder, and measuring the on-site date that is the creep deformation corresponding to theconstruction stage of the beam body.Through the above work, the main conclusions are as follows:Firstly, Summarized the mechanism and influence factors of concrete creep, andcompared to the several kinds of common predictions model each other.Secondly, The effect of non material factors of the beam body that was analysised byelementaryly,and deduced the oretical expressions of the corresponding.Thirdly, Through the different theories and creep model, calculated the deformation ofthe creep of beam in different construction stage, and obtains the reasonable prediction modelthat is comparison of measured data.Finally，By comparing the theoretical and measured data, verify the non material factors(camber and box girder assembly area) effect on the creep of box girder.