The form and strengthening mechanism of the carbon fiber reinfroced polymer(CFRP) strengthening and the bonded steel plate are similar, which are essentially equal to the reinforcement of the components, and can be replaced with each other in the shear and bending reinforcement.The rough method is: if the design value of the tensile strength of the carbon fiber fabric is taken as 2000Mpa, the design value of the tensile strength of steel (Q235) is 200Mpa, and it can be replaced by the principle of 0.1mm thick carbon fiber fabric equivalent to the 1mm thick steel plate.

When replacing, we should pay attention to the following points:

• The elastic modulus of carbon fiber and steel is basically the same, but the tensile strength of carbon fiber is about 10 times of that of steel. Therefore, to give full play to the strength of the reinforced material, the carbon fiber needs to be strengthened to produce more deformation. In other words, under the condition of small deformation, the stress lag effect of the bonded carbon fiber reinforcement is remarkable, so when the bearing capacity of the component is different, the adhesive steel should be preferred, and the bonded steel plate should not be replaced by the bonded carbon fiber.

• To achieve the same bending strength value, the section of the bonding steel plate is much larger, so the bonding steel plate reinforcement to increase the stiffness of the component must exceed the carbon fiber reinforcement. That is to say, if the same bending resistance is added, the deflection and crack width of the bonded steel reinforcement should be less than that of the bonded carbon fiber reinforcement.

• The steel plate can be welded with anchor bars or planted with steel bar anchorage, so the anchoring method is more flexible than carbon fiber.

• Carbon fiber is light and thin, and the construction of carbon fiber is simple. With the same amount of work, the construction period is short, and the efficiency is much higher than that of sticking steel plate.

• Compared with steel products, carbon fiber is inert material, it is not corrosive, and it is not easy to be corroded by harmful medium.

• The cost of sticking carbon fiber at present is lower than that of sticking steel plate. The economy should be analyzed in a comprehensive way.