Renovation and Reinforcement of Prefabricated Slab Houses

The renovation and reinforcement of prefabricated slab houses should select appropriate methods based on the actual conditions of the house and strictly adhere to construction specifications and precautions. Details are as follows:

I. Renovation and Reinforcement Methods

1. Wall-to-Beam Method: Suitable for old prefabricated slab houses with an age of over 30 years. Before construction, a comprehensive assessment of structural safety is required, focusing on checking the width of cracks in the prefabricated slabs (treatment is needed if exceeding 0.3 millimeters) and the connection status with the ring beams (replacement is required if the bolt corrosion rate exceeds 30%). When setting up a temporary support system, steel pipe supports should be placed every 1.2 meters along the length of the prefabricated slabs, and key nodes should use H-shaped steel beams for underpinning (with a cross-section of ≥200200 millimeters). For slab joint treatment, the original filling material should be removed, No. 6 deformed steel bars should be implanted, and C30 fine aggregate concrete should be poured; structural columns should be added at the four corners of the house (with a cross-section of 240240 millimeters) and connected with the floor slab reinforcement. Demolition should follow the principle of 'from the middle to the sides, symmetrically in sections', with the daily demolition amount not exceeding 30% of the total floor slab area, and the stress changes in the support system should be monitored in real-time.
2. Grouting Reinforcement Method: By injecting grout into the walls or foundations, the overall strength and stability are improved, enhancing seismic performance and preventing deformation or crack propagation.
3. Steel Mesh Reinforcement Method: Laying a steel mesh on the surface of walls or floor slabs improves the overall structural integrity and is suitable for scenarios requiring enhanced seismic performance.
4. Steel Plate Bonding Reinforcement Method: Bonding steel plates to cracks in walls or floor slabs increases the load-bearing capacity and is suitable for local deformation or crack repair.
5. Foundation Reinforcement: By increasing the foundation size, deepening the foundation, adding steel mesh, or injecting reinforcement agents, the foundation's load-bearing capacity and seismic resistance are improved.
6. Additional Support Reinforcement Method: Adding support structures to walls or roofs improves overall stability and prevents deformation.
7. Beam Addition Under Slabs: When the load increase is relatively small, carbon fiber can be bonded to the bottom of hollow slabs or steel beams can be added to change the force mode.

II. Precautions

1. Material and Plan Selection: Select high-strength materials (such as carbon fiber cloth, steel plates) or reinforcement methods (such as steel frame collars) based on functional requirements (such as load-bearing capacity, seismic resistance).
2. Construction Detail Control: When bonding carbon fiber cloth, ensure complete adhesion and uniform application of adhesive; when installing steel frame collars, ensure tight connection and firm fixation.
3. Quality Inspection and Acceptance: After reinforcement, use ultrasonic testing, radiographic testing, and other methods to verify quality and ensure compliance with specifications.
4. Environmental and Personnel Protection: Take noise reduction and dust prevention measures during construction to reduce the impact on surrounding residents and the environment.
5. Post-Maintenance Management: Regularly inspect the reinforced parts, promptly address potential hazards, and extend the service life of the house.

Renovation and reinforcement should be evaluated and planned by professional structural engineers, and the construction team should strictly follow technical specifications to ensure safety and effectiveness.