It is a trend to use "lightweight and high-strength" materials in the field of reinforcement. Modern manufacturing and construction techniques provide prerequisites for the transition of reinforcement structural components from passive reinforcement to "active reinforcement". Relevant design specifications and technical standards are also constantly being refined.

Reinforcing member bearing capacity provides high-amplitude recommendations

A technology has the dual characteristics of advantages and disadvantages, and avoid disadvantages based on its advantages. The disadvantage of the mechanical properties of the prestressed carbon fiber board material is that the brittle material and the ductility are not as good as the steel bar, and the brittle failure of the building structure is not allowed, especially under the action of seismic force, it is not conducive to the formation of the plastic hinge of the frame beam of the frame structure. It is recommended to reinforce the secondary beam member is ideal.

Based on the above considerations, it is recommended to refer to the specification requirements for sticking carbon fiber or sticking steel (the increase rate is 40%) when using prestressed carbon fiber composite panels to strengthen the bearing capacity. To increase the prestressing degree, it is suggested to refer to the requirements of the "Code for Design of Concrete" (prestressing degree 0.75). Because of the above improvement of the bearing capacity of components, not only the theory is relatively mature, but also the engineering practice and time have proved the reliability of the engineering structure reinforcement safety.

Structural reinforcement design and verification

The reinforcement design and application of prestressed carbon fiber plates are used. At present, the PKPM and YJK software of the Chinese Academy of Sciences have not yet done an overall analysis of the corresponding reinforcement calculation modules of prestressed carbon fiber plates. The single-member reinforcement bearing capacity calculation and crack and deformation check calculation can be compiled according to the code formula, which is more conducive to the mandatory selection and optimization of reinforcement design and check calculation, and provides a basis for design and check calculation and review by the drawing review unit.

Prestress loss construction control

Although prestressed carbon fiber composite panels have many advantages in reinforcement technology, they have very high requirements on anchor fabrication accuracy and construction quality. The span of industrial and civil building structures is generally relatively small, and it is necessary to control the loss of prestress, because the span is relatively small, the carbon fiber board cannot be fully deformed, and the increase in the bearing capacity of the components is limited. Avoid excessive prestress loss in the construction process and lose the significance of active reinforcement of the structure and the inconsistency with the calculation assumptions, failing to achieve the purpose of reinforcement.

In particular, the bearing capacity of the reinforced components is greatly improved, and more attention should be paid to the control of the hole making and construction quality of the original components. At present, "Code for Acceptance of Construction Quality of Building Structure Reinforcement" GB50550-2010 has lagged behind "Code for Design of Concrete Structure Reinforcement" GB-50367-2013, and there is no relevant technical standard to test and measure the construction standard and effect of prestressed carbon plate reinforcement. The amount and degree of prestress loss during the construction or use of this prestressed carbon plate need to be clarified by engineering practice experience.

The application of prestressed carbon fiber composite panels to structural reinforcement projects is a breakthrough in traditional reinforcement technology, especially for the reinforcement of large-span simply supported reinforced concrete bridges, which exerts the advantages of high strength, light weight, improving component stiffness, reducing component crack width, and preventing stress lag . The use of this technology in the reinforcement of industrial and civil buildings needs to comprehensively consider factors, so that this active reinforcement technology can play a better role in the reinforcement of industrial and civil buildings.