Computing Analysis And Experimental Study On Shringkage And Creep Of Concrete

The creep and shringkage are the inherent time-dependent characteristics of concrete-materials.It has significant influence on the service performance of the prestressed concrete structure,especially the large-scale prestressed concrete bridge.But the mechanics of creep and shringkage is very complicated,and many influential factors should be considered,so it is an important and complicated problem to predict the effect of the creep and shringkage on the prestressed concrete bridge accurately.In general consideration,the prediction model and the analytical method are two critical factors for accurately predicting the effects of the creep and shringkage on the concrete structure,so some research work is carried out in this article.The detailed comparison and commentary on the theoretical principle,factors considered, applicability and the fitting precision to the test data of the current prediction models are carried out , basing on generalizing the mechanics and influential factors systematically.Through analysis on the applicability of the current prediction models to the high-strength and high-performance concrete, the main characteristics and disadvantages of the current prediction models are clear understood.The restraint of non-pestressed steel on the creep and shringkage of concrete is introduced into functional equation by means of the energy principle ,the finite element method and the creep–transformed section properties method.A two-span prestressed concrete girder is analyzed,with consideration on the effect of non-prestressed steels and without consideration on the effect of non-prestressed steels.In addition ,the effect of non-prestressed steels is discussed profoundly with considering the ratio of reinforcement and the distributed way of reinforcement in the concrete section. The method presented in the paper has instruction meanings for analysis on the effects of creep and shringkage of the prestressed concrete structure.The test on the creep and shringkage of high-performance concrete used in SuTong Bridge is carried out on the background of the project-'Research on the Creep and Shringkage and Its Effects on the SuTong Auxiliary Bridge'.The basic property of the creep and shringkage ,and its effect law of the key factors are researched through the tests performed in the laboratory and in the construction site.In addition, the basic mechanical property of high-performance concrete used in the SuTong Bridge is presented ,which provides the necessary analytical parameters for the construction.The test results can be taken as the theoretical basis for the experiment on T girder,and the establishment of the prediction model of the high-performance concrete used in SuTong Bridge.