Research on construction cracks of wide box girder

Abstract

Based on the numerical simulation and field test, combined with the engineering case, this paper studies the causes of construction cracks in wide box girder, and proposes for the first time that the three-dimensional prestressed tendons tension sequence is an important cause of construction cracks in wide box girder. The research results show that: the hydration heat of concrete and the tension sequence of three-dimensional prestressed tendons are the two main reasons for the construction cracks of wide box girder. The lag tension construction technology of transverse and vertical prestressed tendons makes the tensile stress of bottom plate increase rapidly in the early stage of construction, and makes the tensile stress of web plate increase in the construction process, which leads to cracks pouring in the early stage of box girder, but the tension of prestressed tendon has little effect on the final state stress of box girder. The research results of this paper can be used for reference for the construction crack control of prestressed concrete box girder.