Building reinforcement and maintenance 4

The general methods of indirect reinforcement include:

(1) Pre stressing reinforcement method. This method can reduce the stress level of the reinforced components, not only with good reinforcement effect, but also significantly improve the overall bearing capacity of the structure. However, the reinforcement has a certain impact on the appearance of the original structure; Suitable for the reinforcement of large-span or heavy-duty structures, as well as the reinforcement of concrete components under high stress and strain conditions. However, it cannot be used in environments above 60 ℃ without protection, and is not suitable for structures with large concrete shrinkage and creep.

(2) Add support reinforcement method. This method is simple and reliable, but it may damage the original appearance and functional use of the building, and may reduce the use space; Suitable for concrete structure reinforcement where specific conditions permit.

2. The technologies generally used in conjunction with the reinforcement and renovation of concrete structures include:

(1) Transfer technology. It is a general term for technologies such as dismantling columns (or walls, hereinafter referred to as the same), connecting columns to beams, and replacing columns with beams; It belongs to a comprehensive technology consisting of related structural reinforcement, upper structure lifting and resetting, and dismantling of abandoned components; Suitable for reinforcement and renovation of existing buildings; Compared with traditional methods, it has the advantages of shorter construction time, lower cost, and less impact on daily life and production. However, it requires higher technical requirements and needs to be completed by skilled workers to ensure safety.

(2) Reinforcement planting technology. It is a simple and effective connection and anchoring technology for concrete structures; Implantable ordinary steel bars and bolt type anchor bars; It has been widely used in the reinforcement and renovation projects of existing buildings, such as remedying the missing or deviation of steel bars from the design position during construction, reinforcing steel bars by increasing the cross-section of components, extending beams and columns by expanding and lifting the upper structure, adding floor joints to buildings, and planting steel bars for adding shear walls to high-rise buildings.

(3) Crack repair technology. A specialized technique that uses different sealing methods to repair concrete cracks based on their causes, characteristics, and sizes, in order to restore the reduced functionality and durability of the structure caused by cracking; Suitable for the treatment of various types of cracks in existing buildings, but for stress cracks, in addition to repair, corresponding reinforcement measures should also be taken.

(4) Carbonized concrete repair technology (not yet mature). It refers to the technology of suppressing steel corrosion caused by carbonation by restoring the alkalinity (passivation effect) of concrete or increasing its impedance.

(5) Concrete surface treatment technology. It refers to the specialized techniques of using chemical methods, mechanical methods, sandblasting methods, vacuum cleaning methods, water spraying methods, etc. to clean the surface stains, oil stains, residues, and other attachments of concrete.

(6) Concrete surface sealing technology. It refers to the technology of using flexible sealant filling, polymer grouting, coating, and other methods to waterproof, moisture-proof, and crack resistant concrete.

(7) Other technologies. Technologies such as structural and component displacement, and adjusting the natural frequency of structures.