Specifications for Splicing Prefabricated Panels in Houses

The specifications for splicing prefabricated panels in houses cover aspects such as splicing techniques, preparation work, quality control, installation, acceptance and maintenance, and industry standards, as detailed below:

Splicing Technique Categories and Requirements

• Wet Connection Method: Reserve a 50-100mm cast-in-place strip at the joint, arrange connecting reinforcement with a diameter of 8-12mm, pour micro-expanding concrete with a strength grade above C30, and cure for 28 days to reach the design strength. The bonding surface between new and old concrete should be roughened (roughness ≥ 3mm), and it is recommended to use a bonding agent to enhance adhesion.
• Dry Connection Method:
  • Bolt Connection: Embed M16-M24 high-strength bolts at the edges of the prefabricated panels, mechanically fix them with steel connectors, and control the torque within 120-150N·m.
  • Welding Connection: Suitable for galvanized steel floor panels, reserve a 20mm welding edge at the panel edge, use CO₂ gas shielded welding, and ensure the weld height is not less than 6mm.
• Hybrid Connection System: For example, a combination of prestressed steel strand tensioning (control stress 0.7fptk) and cast-in-place strips, balancing construction speed and overall integrity.

Preparation Work Specifications Before Splicing

• On-site Acceptance: Inspect the appearance of the prefabricated panels, ensuring the splicing surface is free from sanding, chipping, or cracking; the position deviation of embedded sleeves and anchor plates should be ≤ 2mm, and the sleeves should not be blocked.
• On-site Storage: Avoid direct contact of the splicing surface with the ground or wooden blocks. For vertical storage, place the splicing surface of wall panels against the side; for horizontal storage, place the splicing surface of laminated panels facing upwards, and place wooden blocks at the designed stress points of the components.
• Pre-treatment of Splicing Surface:
  • Wet splicing: Chisel off the laitance on the concrete bonding surface to expose fresh aggregate, wet it with water 12 hours in advance, and sweep away standing water before splicing.
  • Dry splicing: Grind off rust, oil, and anti-rust paint from the steel bonding surface to expose the metallic luster.

Key Quality Control Points

• Flatness Control: Use a 2m straightedge to check during installation, ensuring the height difference between adjacent panels is ≤ 3mm.
• Seismic Construction: Install seismic reinforcement at the joints, such as 3Φ8 through-length reinforcement for a 2400mm long panel.
• Waterproofing Treatment: Lay a special sealing tape during splicing, with an overlap width of ≥ 50mm.

Construction and Installation Standards

• Foundation Treatment: Ensure the foundation is flat and solid before construction to avoid uneven settlement that may cause cracking or damage.
• Installation Sequence: Follow the design drawings and construction specifications to ensure the correct sequence.
• Support and Fixation: Set up temporary supports during installation and fix them after completion to prevent displacement or detachment.

Acceptance and Maintenance Standards

• Acceptance Criteria: After completion, inspect the quality of the prefabricated panels, installation position, and connection conditions to ensure they meet the design requirements.
• Maintenance and Upkeep: Regularly inspect and maintain, promptly addressing potential safety hazards.

Industry Standard References

Comply with the requirements of the Technical Specification for Prefabricated Concrete Structures (JGJ1-2014): the joint bearing capacity should not be less than 80% of the component itself, and the waterproofing grade should reach Class II.