Application status of carbon fiber(CFRP) laminate in bridge reinforcement engineering

(1) Pasting the carbon fiber laminate in the tension zone of the beam can significantly improve the load-bearing capacity of the beam. With the increase of the thickness of the carbon fiber laminate, the failure form of the reinforced beam is transformed from the peeling of the carbon fiber laminate to the crushing or interface peeling failure of the concrete in the compression zone;

(2) Pasting carbon fiber laminate can improve the bending stiffness of the reinforced beam in the later stage of loading, but the effect of improving the stiffness in the elastic loading stage is not obvious. The increase of the bending stiffness is related to the area of the carbon fiber laminate;

(3) Pasting carbon fiber laminate can effectively suppress the cracks in the late loading stage, but it is not significant for improving the cracking bending moment and early cracking;

(4) In the absence of reliable anchoring measures, most of the reinforced beams have peeled off the carbon fiber laminate. The failure mode of the reinforced beams has obvious brittleness characteristics. The ultimate load-bearing capacity of the reinforced beams with peeling damage is even lower than that of the unreinforced reference beams. ;

(5) Additional end anchoring and local reinforcement measures (such as carbon fiber cloth U-shaped hoop or bead) can effectively prevent the peeling of carbon fiber laminate, significantly improve the mid-span deflection and cross-sectional curvature during failure, and ensure ductile failure of the reinforced beam;

Application status of bridge members reinforced with prestressed carbon fiber laminate

Prestressed carbon fiber laminate reinforcement is a new type of reinforcement and reinforcement technology that has been studied abroad in recent years. There are already many scientific research units and colleges in my country. This technology combines the advantages of ordinary paste carbon fiber materials and prestressed reinforcement technology, while making up for the shortcomings of these two reinforcement technologies.

By applying pre-stress to the carbon fiber laminate, so that it can exert considerable strength in advance, it can not only significantly increase the cracking load, but also increase the structural rigidity and improve the deformation performance of the structure. This allows the prestressed carbon fiber laminate to take full advantage of the high-strength properties of the material during normal use, while also improving the bonding stress distribution at the interface between the carbon fiber laminate and the concrete, thereby delaying the peeling and destruction of the carbon fiber.