Research for Non-Destructive Detection of Vertical Prestressed Tensile Force in Box Girder

Abstract

Fine rolled twisted bars as the vertical prestressed reinforcement has been widely used in the prestressed concrete box girder, but it is hard to effectively control the loss of prestressed force in the practical engineering. Too much loss of prestressed force will lead to diagonal cracks in box girder webs. According to the dynamic theory, take the exposed segment of fine rolled twisted bars as the beam model, take the anchorage segment as a rigid arm and two elastic supports, this article establishes the plane elastic support model of vertical prestressed fine rolled twisted bar. The nonlinear relationship between vertical prestressed tensile force P and the plane stiffness of elastic supports K is established by an indoor experiment, and at the same time the anchoring section stiffness coefficient method is used to verify the effectiveness of this method and conduct an engineering application. This paper provides a theoretical basis for the test of vertical prestressed tensile force in box girder.