Specifications for Splicing of House Prefabricated Panels

The specifications for splicing of house prefabricated panels cover core requirements such as lap length, width, corner treatment, splicing techniques, quality control, and industry standards, as detailed below:

1. Lap Length Requirements
The lap lengths of panels for walls, floors, and roofs must meet differentiated standards: panels for walls should have a lap length of ≥600mm, while those for floors and roofs should be ≥800mm; the lap length of starting panels should be ≥600mm, and seams should not coincide with foundation seams; the minimum lap length between two panels is 600mm, and if exceeded, additional joint panels (length ≥300mm) should be added; the lap length of sandwich partition walls should be ≥900mm. In special scenarios, such as corner lap lengths, they should be further extended to ≥900mm to ensure structural stability.

2. Lap Width Control
Seam widths should be designed differently according to panel type: panels for walls should have a seam width of ≤10mm and ≥5mm, those for floors and roofs should be ≤10mm and ≥8mm, and sandwich partition walls should be ≤6mm; prefabricated panels with a width exceeding 2000mm should have a seam width of ≤15mm. All seam widths should strictly avoid coinciding with foundation seams to prevent stress concentration and cracking.

3. Corner Splicing Specifications
The lap length at corners should be ≥900mm, with a seam width of ≤10mm and a panel end length of ≥300mm. Composite wall panels and multi-layer wall panels should adopt sloped and flattened lap joints with a slope ratio of ≤2:1 to disperse loads by increasing the contact area and enhance seismic performance.

4. Splicing Technique Selection

• Wet Connection Method: Reserve a 50-100mm cast-in-place strip at the seam, arrange Φ8-12mm connecting reinforcement, pour micro-expanding concrete with a strength grade of C30 or higher, and cure for 28 days; the bonding surface between old and new concrete should be roughened (roughness ≥3mm) and coated with an interface agent to enhance bonding.
• Dry Connection Method:
  • Bolt Connection: Pre-embed M16-M24 high-strength bolts, 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 on the panel edge, use CO₂ gas shielded welding, and ensure a weld height of ≥6mm.
• Hybrid Connection System: Combine pre-stressed steel strand tensioning (control stress 0.7fptk) with cast-in-place strips to balance construction speed and integrity.

5. Key Quality Control Points

• Flatness: Use a 2m straightedge to check during installation, with an adjacent panel height difference of ≤3mm.
• Seismic Construction: Seismic reinforcement should be provided at seams, such as configuring 3Φ8 through-length reinforcement for 2400mm long panels.
• Waterproofing Treatment: Lay special sealing tape during splicing, with a lap width of ≥50mm, to ensure a waterproofing grade of II at the seams.

6. Industry Standards and Acceptance
They should comply with the requirements of the Technical Specification for Prefabricated Concrete Structures (JGJ1-2014), with the seam bearing capacity not less than 80% of the component itself. Additionally, the surfaces on both sides of the seam should be cleaned before splicing, the joint should be kept horizontal and straight during the process, and timely inspection and correction should be conducted after completion to ensure compliance with the specifications.