Summary: Although CFRP is a soft cloth, it has brought new impetus to the development of civil engineering in recent years, especially in bridge reinforcement works, especially when the height is limited, its construction technology is relatively simple. So, today I will analyze with you some characteristics of CFRP strengthening bridge stress and points for attention in the use of CFRP.

To improve the bearing capacity of old bridges, carbon fibre cloth with excellent tensile function is posted on the bottom of the girder or the inner wall of box girder with bonding data, so that it can accept the pulling force together with the reinforcing bars placed in the original structure. Compared with other reinforcement methods, CFRP ensures that the original structure is loaded together within the planned load range, and the stress distribution of the original structure is the smallest.

According to the actual situation, CFRP should be used to reinforce the reinforced concrete beam bridge reasonably. When CFRP is used to reinforce the concrete members, the damage shape of the flexural members will be affected along with the improvement of the flexural bearing capacity. When the amount of CFRP is too much, the damage shape of the component changes from the damage caused by the breakage of CFRP to the damage caused by the sudden crushing of concrete. Because carbon fibers are fully elastic material, working with steel bars will weaken the plastic function of steel bars, and the ductility of components will be reduced if the amount of carbon fibers is too much.

Carbon Fibre Sheets (CFRP) are placed along the main tensile stress direction (or orthogonal to the crack) of the bridge, and anchorage ends are set separately at both ends, which can restrain the external cracks of concrete, avoid crack propagation, improve the flexural rigidity of members, reduce the deflection of members and improve the stress condition of beams.

The ultimate damage mode of bridge structures strengthened with CFRP changes to sudden (brittle damage such as breaking or peeling). The ultimate bearing capacity of bridge structures should be calculated according to 2/3 of the tensile strength of CFRP, but not according to the general reinforced concrete.

CFRP can improve the shear capacity of concrete beams. Its effect mechanism is similar to stirrups. Together, CFRP can significantly improve the deformation function of components and enhance the deformation ability of components.