Reinforcement Methods for Prefabricated Slab Roofs

The reinforcement methods for prefabricated slab roofs mainly include the following:

I. Conventional Reinforcement Methods

1. Adding Steel Beams at the Bottom of the Slab: By adding steel beams at the bottom of the prefabricated slab, the stress mode of the hollow slab is changed, enhancing the structural load-bearing capacity. The steel beams need to be professionally designed according to parameters such as span and load to ensure reliable connection with the existing structure.
2. Grouting Reinforcement Method: Grouting is applied to walls or foundations to fill gaps and enhance overall integrity. This method is suitable for stability issues caused by foundation settlement or wall cracks and can effectively improve seismic performance.
3. Steel Mesh Reinforcement Method: A steel mesh is laid on the surface of walls or floors and covered with sprayed concrete or plaster to form a composite structural layer. This method is suitable for situations where local load-bearing capacity is insufficient or surface cracking occurs.
4. Steel Plate Bonding Reinforcement Method: Structural adhesive is used to bond steel plates to the surface of walls or floors to enhance bending and shear resistance. It is essential to ensure proper interface treatment between the steel plate and the base material to avoid voids or detachment.
5. Foundation Reinforcement: Load-bearing capacity is improved by increasing the foundation size, deepening the foundation, or adding steel mesh. Additionally, reinforcement agents or sealing materials can be injected to enhance seismic performance.
6. Adding Support Reinforcement Method: Support structures (such as steel columns or diagonal braces) are added to walls or roofs to disperse loads and limit deformation. The supports need to be reliably connected to the existing structure to avoid local stress concentration.

II. Renovation and Reinforcement of Older Houses

1. Comprehensive Structural Assessment: Before demolition, it is necessary to inspect the crack width of the prefabricated slab (treatment is required if exceeding 0.3 mm), the corrosion rate of bolts (replacement is required if exceeding 30%), and the connection status with the ring beam to ensure structural safety.
2. Temporary Support System: Steel pipe supports are set up every 1.2 meters along the length of the prefabricated slab, and key nodes are underpinned with H-shaped steel beams (cross-section ≥ 200×200 mm) to prevent collapse during demolition.
3. Slab Joint Treatment: The original filling material is removed, No. 6 deformed steel bars are implanted, and C30 fine aggregate concrete is poured to enhance the connection between slabs.
4. Adding Structural Columns: Structural columns measuring 240×240 mm are added at the corners of the house, paired with No. 6 and No. 8 steel bars tied together and connected to the floor slab to improve overall stiffness.
5. Construction Control: The principle of 'middle first, then sides' is followed, with the daily demolition amount not exceeding 30% of the total floor area. The stress changes in the support system are monitored in real-time, and heavy hammer impact demolition is prohibited.

III. Key Considerations The reinforcement plan should be customized according to the actual damage condition of the house, load requirements, and geological conditions. It is recommended to entrust a professional institution for structural verification and construction guidance to ensure that the reinforcement effect meets regulatory requirements.