Impact Analysis of Concrete Shrinkage and Creep on a Prestressed Concrete Box Girder Bridge

This article builds a model of the actual engineering using Midas/Civil, and makes an analysis of the impact on the deformation and stress of the bridge of concrete shrinkage and creep. Midas/Civil software uses the shrinkage and creep formulas in the "highway reinforced concrete and prestressed concrete bridge and culvert design specifications (JTG D62-2004). First, through changing the two parameters of relative humidity and creep coefficient of the model in the shrinkage and creep formulas specified in JTG D62-2004 specification, it analyses the effects of the shrinkage and creep on bridge deformation. Second, in and without the consideration of shrinkage and creep, it makes simulation analysis of the internal forces of the bridge to determine the degree of the influence of shrinkage and creep on bridge stress. By contrasting the parameters under different conditions, it obtains that the linear influence of the different relative humidities on the bridge is 25% in maximum. The concrete shrinkage and creep may also exert a relative great impact on the internal forces of the whole bridge. The stress of the upper flange decreases 1.9 MPa at most and the lower decreases 3.81 MPa at most. Through making an analysis on the impact of changing parameters and considering the shrinkage and creep on the actual engineering model linear and internal force, the author obtained the conclusion of the rule in the influence on a continuous girder bridge under the action of concrete shrinkage and creep, which provides a direction for the design and construction of continuous girder bridge using prestressed concrete.