Study On Design Theory Of External Prestressed Flexural Strengthening With CFRP

With the rapid development of China’s road and bridge infrastructure, increasing traffic and load level, the large number of bridge structures have varying degrees of aging, use function changed and accidental damage, many old bridges’ carrying capacity can not meet the requirements. For this reason, Reinforcement and Maintenance have become increasingly prominent, external prestressed reinforcement is one of the most effective method of reinforcement in many of the bridge reinforcement technology. External Prestressed Reinforcement with CFRP has been favored in the field of the bridge strengthening works for its high tensile strength, light weight, corrosion resistance, fatigue resistance and many other advantages. At present, the overall reinforcement technology is in the initial stage of the pilot study and application, to further expand the scope of application of reinforcement technology, Design theory of the prestressed reinforcement with CFRP is studied systematically in this article.On the basis of the test date, the design strength and reasonable value of the tension control stress of CFRP is explored further in this article; the affect of secondary effects of external CFRP to the short-term stiffness of reinforced member is analyzed and the stiffness’s calculation method of the reinforced beams is elaborated; binding assay, the crack resistance of the reinforced beams is analyzed and the formula of cracks is determined; the calculation method of the ultimate stress increment of CFRP is identified and the simplified calculation method of the flexural capacity of of the simply supported beams reinforced is proposed.Taking into the actual needs of the bridge reinforcement, the study results in this article have a higher theoretical application value. It can provide reliable reference for the design and practical engineering applications of the external prestressed reinforcement with CFRP.