| In order to guarantee the stationarity and safety of trains running in high-speed railway, strict limitation on long-term camber of bridges is needed. Standing on the background of how to control the long-term camber of non-ballast prestressed concrete bridges for high-speed railway, the research on analyzing creep and shrinkage effects in prestressed concrete (PC) bridges has been finished.Considering the characteristics of internal force and structures of simply supported PC bridges, a novel automatically step-up method (ASUM), taking into account the influence of steel arrangement, steel ratio, stress losses of tendons and time-dependent concrete modulus, to analyze creep and shrinkage effects is presented. This method accepts all kinds of expressions of creep and shrinkage, and it is easy to calculate total stress, strain of concrete and steel and deflection of bridge at any time, the expected prediction accuracy will be obtained by further dividing the time-step within duration.After having deduced the combined stiffness matrix considering the contribution of concrete, tendons and non-prestressed steel, a novel mixed analysis method (MAM) based on finite element (FE) and ASUM to analyze time-dependent stress redistribution and structural internal force redistribution due to creep and shrinkage in PC bridges is presented. The obvious advantage of this method is that all time-dependent factors, which are took into account in ASUM, need not to be considered in FE, thus the accuracy of MAM can be easily guaranteed by FE and ASUM, respectively. This method opens a new approach to analyze creep and shrinkage both conveniently and precisely.In view of the fact that prediction of creep and shrinkage with current bridge provision for specific concrete under specific ambience sometimes has a big discrepancy with real values, a new method to obtain the expressions of creep and shrinkage from newly-built PC bridges short-term test results is presented, and relative equations have been established. Therefore, a reliable long-term prediction on effect dueto creep and shrinkage in PC bridges holds a firm bearing point.The current approaches including code methods to calculate stress losses due to anchorage set exist several shortcoming, such as unsuitable to different profiles of tendons or very complicated to compute due to sectional analysis. Based on classical theory of friction when tendons are stretched in post-tensioned concrete members, the unified method to calculate the stress losses in tendons due to anchorage set while considering the affection of reverse friction has been established, these formulae are suitable to be used in computer; also approximate formulae are produced which are suitable to manual computation, they are easy to be applied in research or design.It's the first time clearly and systematically to present the concepts of restraint influence coefficient of steel to strain increment, to curvature increment and to deflection increment due to creep which are different each other. Theoretical formulae are established, and approximate formulae are also obtained while considering the characteristics of common-used concrete and ambient condition of real bridges in china. So, an approximate restraint influence coefficient method to analyze the effect due to creep and shrinkage in PC bridges is put forward, and the equations to estimate second-force due to creep considering influence of steel in system-transferred continuous PC bridges is also established. All these formulae are useful and convenient to bridge research and design for they are simple to handle and bear a good precision.At last, all the factors which may affect the model test mainly for creep & shrinkage effect and the principle for designing model have been discussed, and an approximate method to deduce camber of original bridge from model deflection is presented.
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