Foundation of Prefabricated Concrete Houses
The foundation of prefabricated concrete houses involves multiple aspects such as foundation treatment, foundation form, structural joint design, and construction requirements, as detailed below:
Foundation Treatment:
Foundation treatment is a crucial step to ensure the stability of the house. Common methods include compaction, which involves using a pneumatic hammer or heavy road roller to compact the original foundation soil layer, increasing soil density to meet load-bearing capacity requirements; soil replacement, which replaces loose soil with higher-density materials, though it is more costly; pile driving, which embeds reinforced concrete piles into soft soil layers to enhance stability, suitable for small buildings; replacement cushioning, which uses a 3:7 lime-soil mixture for layered backfilling (compaction coefficient ≥ 0.97) with a cushion thickness of 800mm; and drainage measures, which involve setting up a gravel blind ditch (cross-section 300×300mm) at the bottom of the cushion, filled with 5-10mm gravel to drain accumulated water.
Foundation Form:
The foundation form should be selected based on the house load and geological conditions. Reinforced concrete strip foundations adopt an inverted T-shaped cross-section, with a foundation height of 600mm (step height 300mm), width of 1200mm (footing width 800mm), and reinforcement configuration of Φ16@150 (longitudinal) and Φ12@200 (transverse). The concrete cover thickness is 40mm (water-facing side) and 30mm (back side). Prefabricated box transformer foundations have wall thicknesses of 200/250/300/350mm, a load-bearing capacity of 30 tons, a concrete grade of C30, a service life exceeding 50 years, moisture resistance, and ease of installation.
Structural Joint Design:
Structural joint design directly affects the overall integrity of the house. The foundation ring beam has a cross-section of 240×300mm, equipped with 4Φ12 longitudinal bars and Φ6@200 stirrups, and is cast integrally with the foundation beam to enhance crack resistance. Embedded iron parts use -10mm thick steel plates (300×300mm) and 4Φ16×300mm anchor bars for lifting connections of prefabricated houses. Deformation joints are set every 30m along the length of the house, with a 20mm wide gap filled with bituminous hemp fiber to accommodate temperature deformations.
Construction Requirements:
Construction must strictly control materials and processes. In terms of materials, cement, steel bars, etc., must comply with national standards and design requirements. The construction process includes foundation treatment, foundation construction, installation of prefabricated components, and roof waterproofing. Construction details should focus on the precision of prefabricated component splicing and the quality of waterproof layer laying to ensure compliance with design specifications.
