The main reasons for steel structure reinforcement are as follows:

(1) Steel structure defects caused by planning or construction, such as insufficient weld length, excessive reinforcement cutting, excessive section weakening, etc.

(2) After the structure has been used for a long time, it has corrosion, abrasion and abnormal operation to varying degrees. It causes structural defects and seriously weakens the section of structural members.

(3) The change of process production conditions increases the load of the structure, and the original structure cannot be used to.

(4) The quality of steel used does not meet the requirements.

(5) Accidents and natural disasters seriously damaged the structure.

(6) The deformation and destruction of the structure are caused by the foundation subsidence.

Reinforcement principle of structure or component

(1) Reinforcing bars should be produced as little as possible without production, because the loss caused by stopping production is often several times or dozens of times of the cost of reinforcing bars. Whether to stop production and strengthen under load depends on the stress and strain state of the structure. When the internal stress of general members is less than 80% of the planned strength of steel, and the damage and deformation of members are not too serious, the non-stop reinforcement method can be used.

(2) The structural reinforcement scheme shall be easy to make, construct and inspect.

(3) Structural fabrication and assembly shall be carried out outside the production area as far as possible.

(4) High strength bolts or welding shall be used as the connecting reinforcement. When high-strength bolts are used for reinforcement, the bearing capacity of the weakened drilling section shall be checked; When welding reinforcement is selected, the stress of the original reinforcement caused by the actual load shall be better than 60% of the planned strength of the reinforcement, and the limit shall not exceed 80%, otherwise corresponding measures shall be taken before welding.