Reinforcement of Old Houses with Prefabricated Panel Structures

The reinforcement of old houses with prefabricated panel structures can be achieved through various methods. It is necessary to select an appropriate plan based on the structural assessment results and strictly control construction details and acceptance management. The specific reinforcement methods and precautions are as follows:

I. Common Reinforcement Methods

1. Grouting Reinforcement Method
   By injecting cement-based grouting materials into walls or foundations, pores and cracks are filled, enhancing the overall strength and compactness of the structure. This method can effectively improve seismic performance, prevent deformation expansion, and is particularly suitable for cases of foundation settlement or loose walls.

2. Steel Mesh Reinforcement Method
   A steel mesh is laid on the surface of walls or floors, and concrete is sprayed to form a composite structural layer. The steel mesh is fixed with anchor bolts and works in conjunction with the original structure, significantly improving crack resistance and shear capacity. It is suitable for floors or walls with insufficient load-bearing capacity.

3. Steel Plate Bonding Reinforcement Method
   Structural adhesive is used to bond steel plates to cracked or deformed areas, distributing the load through the high-strength properties of the steel plates. Attention should be paid to the bonding quality between the steel plates and the original structure to avoid voids. This method is suitable for components with severely insufficient local load-bearing capacity.

4. Foundation Reinforcement
   For issues of insufficient foundation bearing capacity, the base area of the foundation can be expanded, the foundation depth can be increased, or steel meshes and reinforcing agents can be added. For example, pouring concrete around the original foundation to create an enlarged head enhances stability.

5. Additional Support Reinforcement Method
   Steel supports or concrete columns are added to walls or roofs to form a spatial load-bearing system. The supports need to be reliably connected to the original structure to avoid local stress concentration. This method is suitable for reinforcing large-span prefabricated panel structures.

6. Panel Bottom Reinforcement
   When the load increase is relatively small, carbon fiber cloth can be bonded to the bottom of hollow panels to enhance load-bearing capacity using its high tensile strength. If the load increase is significant, steel beams need to be added to change the load transfer path, and the specifications of the steel beams should be determined through structural calculations.

7. Wall-to-Beam Conversion Method
   Some walls are demolished and reinforced concrete beams are added to transfer the upper load to the side walls or columns. This method is suitable for functional renovations that require the removal of load-bearing walls.

II. Reinforcement Precautions

1. Pre-construction Assessment
   It is necessary to inspect the crack width of prefabricated panels (treatment is required if exceeding 0.3 mm), the rust rate of bolts (replacement is required if exceeding 30%), and set up a temporary support system (steel pipe supports are set every 1.2 meters, and key nodes are replaced with H-shaped steel beams).

2. Material and Process Control
   Select materials according to the reinforcement objectives: carbon fiber cloth or steel plates for insufficient load-bearing capacity; supports or steel structural collars for seismic requirements. During construction, ensure that the carbon fiber cloth is fully bonded and the steel structural collars are tightly connected.

3. Quality Acceptance
   After reinforcement, ultrasonic testing, radiographic testing, and other methods are used to verify the bonding quality and internal defects, ensuring compliance with the requirements of the "Code for Design of Concrete Structure Reinforcement".

4. Environment and Maintenance
   During construction, take noise reduction and dust prevention measures to reduce the impact on the surrounding area. After reinforcement, regularly inspect the connection nodes and material aging, and promptly address potential hazards.