Specifications for Rebar Layout in Prefabricated Houses

The rebar layout in prefabricated houses must strictly adhere to the structural type and purpose, with key specification points as follows:

I. Rebar Layout in Prefabricated Slabs

1. Position and Type: Rebars are typically arranged in the tensile zone (bottom) to compensate for the insufficient tensile strength of concrete. Ordinary prefabricated slabs use single-layer rebars, suitable for scenarios with small spans and light loads; two-way slabs (with an aspect ratio close to 1:1) require a two-way rebar mesh to withstand bending moments in both directions; prestressed prefabricated slabs enhance crack resistance by pre-applying tension, with rebars still located in the tensile zone.
2. Construction Requirements: The thickness of the rebar protective layer should be no less than 15mm to prevent corrosion; spacing and diameter are determined based on the design load, with common spacing of 100-200mm and diameters of 6-12mm; negative moment rebars should be added at the slab ends and supports to resist local stress concentrations.

II. Rebar Layout in Columns

1. Cross-Section and Main Rebars: It is recommended to use a 300mm×300mm square cross-section, with 4 HRB400-grade rebars with diameters of 12-14mm selected as the main rebars, evenly arranged along the four corners of the column to ensure bending and shear resistance.
2. Stirrup Configuration: Stirrups should be selected as HPB300-grade rebars with diameters of 6-8mm, with a conventional spacing of 150-200mm; the spacing should be densified to no more than 100mm within 1/6 of the column height at the top and bottom of the column to enhance shear resistance at the joints.
3. Anchorage Requirements: The bottom of the column must be anchored into the independent foundation by at least 300mm, and the foundation embedment depth should not be less than 500mm to ensure structural stability.

III. Connection Structure Between Columns and Prefabricated Slabs

1. Concrete Ring Beam: Pour a concrete ring beam at the top of the column with a width consistent with the column and a height of 200-300mm, equipped with rebars of the same specification as the column's main rebars to form an integrated support structure.
2. Embedded Steel Plate Welding: Embed a steel plate with a thickness of no less than 8mm at the top of the column, and weld the anchor rebars at the end of the prefabricated slab to the steel plate to enhance connection reliability.

IV. Material Selection and Quality Inspection

1. Material Selection: Rebars should preferably be HRB400 or HRB500-grade hot-rolled ribbed rebars, and the concrete strength grade should be no lower than C30 to ensure material performance meets standards.
2. Inspection Points: Check whether the rebar specifications, quantity, and spacing comply with the design; ensure that the rebars are firmly bound and accurately positioned, and that the protective layer thickness meets standards; clean debris from the formwork and keep it moist before concrete pouring.

Industry Standard References: It is necessary to follow the specific requirements of the Code for Design of Concrete Structures (GB50010) and the Quality Inspection Standard for Prefabricated Concrete Components (GB/T51231).
Precautions: Lifting prefabricated slabs involves high-altitude work, requiring the use of safety harnesses and protective nets, and should be operated by professionals; after construction, the load-bearing capacity should be tested, and exceeding the design load is strictly prohibited (the rated load-bearing capacity of ordinary prefabricated slabs is 200-400 kilograms per square meter).