The prestressed CFRP laminate has been widely used in the structural strengthening in recent years with its unique advantages. Applying prestress on the carbon fiber laminate, carbon fiber laminate in bearing load structure transfer stress before it has been at a high level of stress, played a certain strength in advance, so as to make full use of its high strength, belongs to the active reinforcement method, the reinforcement effect is very obvious.

The prestressed CFRP laminate system on the market is usually composed of three parts: carbon fiber laminate, anchorage and carbon fiber laminate glue. In order to achieve a certain reinforcement effect, these three parts need to work together. However, compared with other strengthening method, the prestressed CFRP laminate system is obvious, there will be a variety of problems in the construction operation, we will pay more attention.

1. A horizontal or vertical fracture of prestressed CFRP laminate

There are two reasons for the fracture of carbon fiber laminate: 

First, the quality of carbon fiber laminate is not qualified. Carbon fiber laminate is the carbon fiber in the same direction using resin infiltration, hardened and formed, with high strength. In a certain length, how much the carbon fiber laminate can bend and not be destroyed depends on the bonding material and the production process. The surface of the carbon fiber strip have different types of faults, the larger straightness deviation will make carbon fiber strip in high stress concentration, stress or anchorage end damage phenomenon of tension in the process of stress state in more than a dozen or even more than 20 tons, is extremely easy to occur failure to bring no small trouble to the operation of site safety.

On the other hand, the construction or anchor installation causes the transverse shear resistance of the carbon fiber plate, or the longitudinal eccentric force of the carbon fiber strip. The strength of carbon fiber strip is anisotropic, and it is very easy to break the carbon plate because of improper operation.

2. The slipping of carbon fiber strip

Because the gap between the clamp and the clamp is too large, the clamping force is insufficient, which causes the CFRP strip to slip when the prestressed. The slip of carbon fiber strip affects prestressing, which is not good to the strengthening of the structure.

3. The bounding box failure

The bounding box plays a very important role in the effect of tension anchorage. The strength of the screw is not enough will lead to the failure of the bounding box, and can not reinforce the structure.

4. Failure of anchor block

In the installation of prestressed CFRP laminate, the failure of the anchor block is caused by the error of the anchor block installation.

5. Jack problem

Jack is a special device for prestressed carbon strip. Jack oil leakage or exceeding the tonnage will affect the construction. Therefore, we should strictly check the parameters of Jack before use, and avoid overpressure and overload.