Prediction Model of Index Type Shrinkage and Creep for High-Strength Concrete and Its Engineering Application

The shrinkage and creep is an important factor causing long-term deformation of long span prestressed concrete(PC) box girder bridges.In the current analysis of the long-term deformation of the bridges,the CEB-FIP 90 model is usually employed and the errors of calculation by the model are great.To minimize the errors of the calculation,a three-span PC continuous box girder bridge was cited as an example and the standard creep tests for the high-strength concrete having the same mix proportioning with that of the bridge were made.The measurement data were fitted,the index type shrinkage and creep model was obtained and the creep coefficients were modified in accordance with the actual dimension effect,humidity effect,reinforcement ratios and load holding years of concrete components of the bridge.The long-term deformation of the bridge calculated in accordance with the model is well agreeable with the measured deformation,verifying that the model has even higher prediction precision as compared to that of other existing shrinkage and creep models.