In the new era, people put forward higher requirements for the practicability, aesthetics, safety and durability of construction projects, which has increased many challenges to the development of the construction industry. Among them, appraisal and evaluation of existing buildings, structural strengthening reinforcement and rectification are one of the typical problems. According to data, more than 40% of the current 6 billion square meters of housing construction needs to be verified and strengthened in stages and batches. It can be seen that the reinforcement of construction engineering structures has gradually evolved into one of the important branches of the construction industry.

Structural strengthening reinforcement

Reinforcing the structure is essentially to enhance the safety of the building structure. The construction of a building structure is a complicated task, and many factors need to be considered in specific practice. In the process of selecting a structural strengthening reinforcement method and technology, the following principles should generally be followed:

(1) Construction should reduce or avoid production stoppages. This is mainly because the economic losses caused by production stoppages are usually more than several times, or even dozens of times, the cost of reinforcement. How to achieve non-stop production reinforcement is closely related to the stress and strain state of the structure. Generally, the internal stress of the component is required to be less than 80% of the design strength of the steel, and when the component is damaged or the deformation is not obvious, it should be able to load the reinforcement method without stopping production.

(2) The reinforcement scheme is convenient for production, construction and inspection.

(3) Structural manufacturing and assembly operations are best performed outside the production area.

(4) It is best to use high-strength bolts or welding for reinforcement operations.

Common structural strengthening reinforcement methods

Reinforcement of masonry structure: direct reinforcement method, indirect reinforcement method

Concrete structure: Enlarge the cross-sectional area and strengthen the outer profile steel

Prestressed reinforcement: it is equivalent to the application of prestressed steel tie rods or profiled steel braces to strengthen the building structure

Steel structure reinforcement: commonly used steel structure reinforcement methods to reduce load, adjust structural calculation graphics, enhance the cross-section and joint strength of original structural members, and inhibit crack propagation.

The development trend of structural strengthening reinforcement technology

Fiber reinforced polymer(FRP)composite reinforcement method

The application process of fiber composite reinforcement in my country is relatively short, but it has obvious characteristics and excellent effects. It has become the focus of research in scientific research institutes, universities and colleges, and has high practicability. Especially the stick fiber reinforcement method is more mature. Combining with previous research results, summarize the issues that need to be addressed in the actual application of fiber reinforcement:

(1) Increase the depth of research on the mechanical properties of fiber reinforced components;

(2) Analyze the influence of fiber materials on the formation of joint reinforcement;

(3) The strength of fiber-reinforced components is significantly reduced under high temperature conditions. At this time, how to improve the performance of the reinforcement material and improve the fire resistance of the material is an important topic in the follow-up research;

(4) Strengthen theoretical research related to anti-fatigue reinforcement issues;

(5) Simplify the construction process and reduce the cost on the basis of ensuring the quality of structural strengthening reinforcement.

In recent years, with the rapid development of science and technology, new reinforcement materials and methods have emerged continuously. New technology has great advantages, so the scope of application continues to expand, but it cannot completely replace the traditional reinforcement technology. This requires technicians to complement the advantages of various reinforcement methods, and then provide more reliable technical support for the reinforcement of building structures.