Requirements for Rebar Layout in Prefabricated Houses

The rebar layout in prefabricated houses should be determined based on the structural type and design requirements. Key points are as follows:

I. Rebar Layout for Columns (Load-Bearing Columns)

1. Main Rebar Configuration: Adopt a 300mm×300mm square cross-section with four HRB400-grade rebars of 12-14mm in diameter evenly arranged along the four corners of the column to ensure flexural capacity.
2. Stirrup Densification: Use HPB300-grade rebars of 6-8mm in diameter for stirrups, with a regular spacing of 150-200mm. Densify the stirrups to within 100mm at the top and bottom 1/6 of the column height to enhance shear capacity.
3. Foundation Anchorage: Anchor the column bottom into the independent foundation by at least 300mm, with a foundation embedment depth of no less than 500mm to prevent column bottom slippage.

II. Rebar Layout for Prefabricated Slabs

1. On-Site Prefabricated Solid Slabs:
   • Load-Bearing Rebars: Arrange in the tensile zone at the bottom of the slab, using HRB400-grade rebars of 10-12mm in diameter with a spacing of 150-200mm.
   • Distribution Rebars: Arrange HPB300-grade rebars of 6mm in diameter perpendicular to the load-bearing rebars with a spacing of approximately 250mm to assist in load-bearing and control cracking.
   • End Anchorage: Reserve anchoring rebars for connection with the column top to ensure integrity.
2. Finished Prefabricated Hollow Slabs: No on-site rebar arrangement is required, but confirm that the rated load-bearing capacity (200-400kg/m²) meets usage requirements.

III. Connection Structure between Columns and Prefabricated Slabs

1. Concrete Ring Beam: Pour a 200-300mm high ring beam at the column top, with a width consistent with the column, and equip it with rebars of the same specification as the column main rebars to form integral support.
2. Embedded Steel Plate Welding: Embed a steel plate with a thickness of ≥8mm at the column top and weld the anchoring rebars of the prefabricated slab to the steel plate to enhance connection stability.

IV. General Design Principles

1. Rebar Position: Prioritize arranging rebars in the tensile zone (bottom) of prefabricated slabs to utilize the tensile properties of rebars to compensate for the insufficient tensile properties of concrete.
2. Two-Way Slab Rebar Arrangement: When the length-to-width ratio is close to 1:1, arrange a two-way rebar mesh to withstand bending moments in both directions.
3. Material Selection: Use HRB400/HRB500-grade hot-rolled ribbed rebars for rebars and concrete with a strength grade of no less than C30.

V. Construction and Acceptance Points

1. Cover Thickness: Ensure a rebar cover of ≥15mm to prevent corrosion.
2. Quality Inspection: Check the specifications, quantity, spacing, and binding firmness of rebars to ensure compliance with design requirements.
3. Load-Bearing Test: Test the load-bearing capacity after construction and strictly prohibit overloading.

Industry Standard References: Follow the "Code for Design of Concrete Structures" (GB50010) and the "Quality Inspection Standard for Prefabricated Concrete Components" (GB/T51231). Specific projects should be adjusted and operated by professionals.