Research on Twice-Prestressed Composite Beam and Its Application in Highway Bridges

Abstract

The concept, basic principle, and characteristics of twice-prestressed composite beam are introduced, and the mechanical performance, deformation performance, and creep stress redistribution of the horizontal interface of twice-prestressed beam are discussed. In addition, previous studies regarding the application of twice-prestressed composite beams in highway bridges are summarized and analyzed. It is concluded that the twice-prestressed composite beam can decrease the creep camber of a prestressed concrete beam by more than 50%; thus, the contradiction of reducing creep camber and improving the safety of section crack resistance can be effectively resolved. Moreover, twice-prestressed composite beam can save approximately 10% of prestressed tendons and has comprehensive technical and economical advantages in highway ultrathin beam bridges and urban overpass bridges. Future research of twice-prestressed composite beam will focus on the design method, connection model, structure, and shear performance of horizontal interface in addition to the construction technology.