Stochastic Analysis Of Shrinkage And Creep Effects For Prestressed Concrete Continuous Beam Bridge

The prestressed concrete continuous beam bridge is affected sensitively by concrete shrinkage and creep for its complex construction and structure systemchanges. The creep and shrinkage of concrete is easily i MPacted by lots of randomfactors, so its long-term effects show a remarkable randomness. Taking three existingbridge as engineering example, a stochastic analysis was carried out in the thesis about the shrinkage and creep effect of prestressed concrete continuous beam bridges, with consideration of several main random factors probably causing the shrinkage and creep effect of bridges. The following studies are mainly involved:(1) Domestic and international research datas about concrete shrinkage and creep are widely collected. The generation mechanism, influencing factors and some latest research progress of concrete shrinkage and creep are summarized, the calculation theory of concrete shrinkage and creep is inductived in this part as well.(2) The simulation analysis of the construction process for three prestressed concrete continuous beam bridge is carried out using orderly-erecting analysis method, and obtain deflection and stress of each main girder segment in each construction stages.(3) Considering the affecting variables’ randomness of concrete shrinkage and creep, a stochastic method for the structural shrinkage and creep effects(deflection、stress) was used as the analysis theoretical basics for this thesis which is a technique combining the Response Surface Method with Monte Carlo sampling.(4) Based on the above method, a stochastic analysis about the shrinkage and creep effects(deflection、stress) of three prestressed concrete continuous beam bridge in the case of the main beam is overweight was conducted in this thesis. The statistic characteristics and the probabilistic prediction of structural deflection and stress were achieved.(5) With response surface function, a i MPact analysis of random variables is defined. It can be found that the randomness of ambient relative humidity has the most important influence on the variability of the concrete shrinkage and creep effects(deflection、stress) and the randomness of compressive strength of concrete and loading age has relative weaker influence. However, the randomness of theoretical thickness of the component and age starts to contract has the weakest influence on the variability of the concrete shrinkage and creep effects.