How to Reinforce Prefabricated Slab Houses

The reinforcement of prefabricated slab houses requires the selection of scientific methods based on the actual condition of the house. The following are common reinforcement methods and precautions:

I. Common Reinforcement Methods

1. Grouting Reinforcement Method Inject cement-based or chemical grouting materials into wall cracks or foundation voids through pressure equipment to fill the gaps and enhance the overall structural integrity. This method is suitable for wall cracking caused by foundation settlement or loosening at the joints of prefabricated slabs. It can effectively improve seismic performance and prevent crack propagation.

2. Steel Mesh Reinforcement Method Lay a steel mesh with a diameter of 6 - 8mm on the surface of walls or floors, fix it with anchor bolts, and then pour fine aggregate concrete. This method can significantly improve the flexural and shear resistance of the structure, especially for areas with insufficient floor bearing capacity or severe wall cracking.

3. Steel Plate Bonding Reinforcement Method Use structural adhesive to bond steel plates to the bottom of prefabricated slabs or on both sides of wall cracks, enhancing the bearing capacity through the coordinated stress between the steel plates and the original structure. Note that the thickness of the steel plate should not exceed 6mm, and anti-corrosion treatment is required. This method is suitable for the repair of local insufficient bearing capacity.

4. Section Steel Reinforcement Method Install L-shaped or channel-shaped steel members at the four corners of prefabricated slabs to form an octagonal support system. This method can directly improve the mid-span bearing capacity of the floor and is suitable for the reinforcement of large-span rooms. However, it is necessary to ensure reliable connection between the section steel and the original structure.

5. Carbon Fiber Bonding Method Bond high-strength carbon fiber cloth along the stress direction of the prefabricated slabs and form a composite reinforcement layer through epoxy resin impregnation. This method is lightweight and easy to construct, and can increase the flexural stiffness of the floor by 20% - 50%. It is suitable for reinforcement in light-load environments.

II. Key Points of Construction

• Pre-construction Safety Assessment: Before construction, it is necessary to detect the crack width of prefabricated slabs (cracks wider than 0.3mm need to be treated), the rust rate of bolts (bolts with a rust rate higher than 30% need to be replaced), and the amount of foundation settlement. The assessment results determine the feasibility of the reinforcement plan.
• Temporary Support System: Set up steel pipe supports every 1.2 meters along the length of the prefabricated slabs and use H-shaped steel beams for transfer at key nodes to ensure structural safety during demolition or reinforcement.
• Demolition Control: The daily demolition amount should not exceed 30% of the total floor area, and symmetric demolition should be carried out. Monitor the stress changes of the supports in real-time, and it is forbidden to use heavy hammers for impact demolition.
• Quality Acceptance: After reinforcement, bearing capacity tests and deformation monitoring should be carried out to ensure compliance with the requirements of the "Technical Code for Seismic Reinforcement of Buildings".

III. Handling of Special Cases

• Houses with Fire Damage or Severe Settlement: If the strength of the prestressed steel bars is lost or the structural cracking caused by foundation settlement exceeds the standard limits, reinforcement around the perimeter will have limited effects, and it is recommended to demolish and rebuild.
• Houses with Non-structural Aging: The living comfort can be improved through methods such as crack repair (using epoxy resin grouting), pipeline replacement (using flexible joints), and the installation of insulation layers, without the need for large-scale reinforcement.