Stress Characteristics Analysis On Prestressed Concrete Continuous Box Girder Reinforced With CFS

Prestressed concrete continuous box girder bridge is common bridge type in China on account of its large torsional rigidity, rational stress distribution of cross section, gentle deflection curve of main girder and driving comfort. However, there are many cracks in top plate, web plate, bottom plate, diaphragm plate, and truss plate of box girder because of overload, prestress loss, and low design load. These cracks badly affect durability safety and normal use of box girder. So it is essential to take effective strengthening measures to ensure using function of bridge. CFS is applied in strengthening engineering of bridge structure because of its advantages of high tensile strength, light weight, high corrosion resistance and durability. Combined with Hunan science fund projects"ultimate capacity analysis prestressed concrete continuous box girder strengthened with CFS", the prestressed concrete continuous box girder strengthened with CFS is studied in finite element analysis.According to nonlinear finite element theory, the nonlinear finite element of prestressed concrete continuous box girder strengthened with CFS is built with APDL of ANSYS. Then the methods of building model are modified, including of meshing, element types, parameter selection boundary conditions and convergence criteria, and then the calculated values are made anastomosed with test values, so that the finite element modeling method of simulation of whole process of strengthening box girder with CFS could be obtained.Based on the successful simulation of strengthened box girder with CFS, though comparative analysis, it is proved that CFS could improve ultimate bearing capacity of box girder and delay the coming out of cracks. However, CFS would increase shear lag effect of box girder. Theoretical basis of strengthening design of CFS is provided.The concrete continuous box girders model of different prestress loss are built, though comparative analysis it is proved that the effect of strengthening to prestressed loss bredge with CFS is fine.