Comprehensive Simulation Method on Shrinkage and Creep Effects of Concrete in Structures of Bridges during Whole Time-Varying Process

A comprehensive simulation method on shrinkage and creep effects of concrete during time-varying process which is relatively precise, simple and practical is studied, considering that the effects vary and interact each other during time, in order to analyze shrinkage and creep effects of concrete structures in continuous and composite bridges with complex construction stages to ensure their safety. The finite element incremental method is applied as theoretical basis, which works through calculating and accumulating the results in every incremental load step. By setting time steps according to incremental loads, the finite element incremental method can simulate well shrinkage and creep effects on concrete structures during whole time-varying process. Secondary development is carried out with APDL to improve the calculating approach of temperature effects and the metal creep criteria in the finite element software ANSYS, so a finite element comprehensive simulation method is formed for calculating simultaneously shrinkage and creep effects of concrete in structures of bridge during whole time-varying process. Using standard shrinkage and creep models in specifications, shrinkage and creep effects of a concrete column with multiple loading cases are analyzed simulatedly and theoretically during time-varying process. Appling an experimental creep model, creep effects are computed on experimental non-glued prestressed beams of high performance fly ash concrete. The results are studied by comparing them between simulation and theory and between simulation and experiment. The result shows that shrinkage and creep effects obtained by the comprehensive simulation method display obvious characters of loading stages and time-varying process, the simulation results are in good agreement with the theoretical calculation results during the whole time-varying process. The result also shows that the comprehensive simulation method can easily be combined with experiment, and can make full use of findings of experimental researches, and the calculated results from this method are in good agreement with those measured values of modal beams in the experiment. Therefore, the comprehensive simulation method is completely feasible and easy to connect with specifications and experimental researches, and the whole calculation can be conducted automatically with the finite element software, so the method is very convenient and easy for wide application.