Renovation of Prefabricated Slab Structure Houses

The renovation of prefabricated slab structure houses requires a comprehensive approach involving assessment, renovation measures, construction sequence, and policy utilization to ensure safety and compliance.

I. Structural Safety Assessment Before Renovation

1. Inspection of Cracks in Prefabricated Slabs: Focus on detecting the width of cracks at the production points of prefabricated slabs. If the width exceeds 0.3 millimeters, special treatment (such as grouting repair or reinforcement) is required to prevent crack propagation from affecting structural safety.
2. Inspection of Connection Status: Check the corrosion rate of connecting bolts between prefabricated slabs and ring beams. If the corrosion rate exceeds 30%, replacement is mandatory to ensure the bearing capacity of connection nodes meets requirements.

II. Reinforcement Measures During Renovation

1. Reinforcement of Roof and Walls:
   • Recast concrete roofs to enhance waterproofing performance and structural stability.
   • Perform plastering and steel bar grouting on exterior walls to strengthen load-bearing capacity and tensile properties.
2. Temporary Support System:
   • Before construction, erect temporary supports, placing steel pipe supports every 1.2 meters along the length of the prefabricated slabs. Use H-shaped steel beams (cross-section ≥ 200*200 millimeters) at key nodes for underpinning to prevent structural instability during demolition.
3. Treatment of Slab Joints:
   • Remove the original joint-filling materials, implant No. 6 threaded steel bars, and pour C30 fine aggregate concrete to repair slab joints and enhance overall integrity.
4. Addition of Structural Columns:
   • Add structural columns (cross-section 240*240 millimeters) at the four corners of the house, reinforced with No. 6 and No. 8 steel bars, and connect them to the floor slabs to enhance seismic resistance.

III. Construction Sequence and Precautions

1. Principle of Segmented Demolition:
   • Adopt a symmetrical demolition method of 'middle first, then sides,' with a daily demolition volume not exceeding 30% of the total floor area to avoid sudden changes in local loads.
2. Real-time Monitoring:
   • Monitor stress changes in the support system during demolition to ensure the safety of temporary supports.
3. Prohibition of Impact Demolition:
   • Strictly prohibit the use of heavy hammers for impact demolition to prevent shock damage to the foundation and surrounding structures.

IV. Policy Utilization and Renovation Directions

1. 'Original Demolition and Reconstruction' Policy:
   • Old houses can be demolished and rebuilt, with the new floor plan or actual usable area increased by up to 30%. However, modern structures (such as elevators, scientific lighting, functional zoning, and underground piping) must be redesigned.
2. Compliance Requirements:
   • Renovation must comply with local planning and building codes to ensure the new structure is safe and functionally reasonable.

Through systematic assessment, scientific reinforcement, standardized construction, and policy utilization, the renovation of prefabricated slab structure houses can achieve safety upgrades and functional optimization.