Experimental Research on the Creep Behavior of Twice Prestressed Concrete Beam

Due to the greater additional stress of prestressing, many serious problems – such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking frequently occurred in the prestress tensioning process of medium or short span prestressed concrete beam bridge. To solve these problems, a new type of twice prestress technology was innovatively proposed in this work. Through theoretical and experimental comparison between this new structure and the traditional prestressed structure, it was found that the application of prestressing twice can significantly improve the mechanical and deformational performance of the low height beam in the construction process and also for long-term use. In addition, a theoretical solution to calculate creep strain and deformation due to twice prestressed with respect to time t were derived in this paper. Finally, the work concluded that this new structure will make it a bright application perspective for the medium and short span prestressed beam bridge to control the deformations.