Rebar Layout Diagram for Prefabricated Slab Houses

The rebar layout for prefabricated slab houses should adhere to the following key points to ensure structural safety and stability:

1. Rebar Layout in Prefabricated Slabs The load-bearing rebars (usually steel wires or rebar meshes) in prefabricated slabs are primarily arranged at the bottom of the slab to bear tensile stress; only a small number of structural rebars are needed at the top to resist stress caused by temperature changes or shrinkage. This arrangement conforms to the mechanical principle of "tensile zone at the bottom" and effectively enhances the slab's flexural capacity. If the prefabricated slab is a two-way slab (i.e., with a length-to-width ratio less than 2), load-bearing rebars should be configured in both directions; for one-way slabs, main rebars are arranged only in the short-span direction, with distribution rebars in the long-span direction.

2. Reinforcement at Room Corners The four corners of a room are areas of concentrated structural stress, prone to cracking due to temperature changes or uneven foundation settlement. Therefore, radial rebars or a梅花-shaped (plum-blossom-shaped) arrangement should be laid at the corners, with a length generally one-fourth of the room's short side, and must be located within the upper rebar mesh. Radial rebars can disperse corner stress, while the plum-blossom arrangement (i.e., crossed rebars) enhances local crack resistance. For irregularly shaped rooms (e.g., L-shaped, T-shaped), additional reinforcing rebars should be added at the corners.

3. Rebar Treatment Around Openings All openings (such as doors, windows, and pipe penetrations) must be enclosed with additional rebars to form a closed "rebar frame," preventing structural cracking due to weakening at the openings. The specifications (diameter, spacing) and quantity of additional rebars should be determined based on the opening size:

• Small openings (width ≤ 300mm): Two rebars with a diameter of not less than 8mm should be configured on each side, with a length not less than the opening width plus 500mm;
• Large openings (width > 300mm): Hidden beams or reinforcing frames should be set according to design requirements, with rebar diameters of not less than 12mm and spacing ≤ 150mm. Additional rebars should be reliably connected to the original rebar mesh (e.g., by tying or welding) to ensure continuous stress transfer.

4. Rebar Layout in Composite Slabs Composite slabs consist of a prefabricated bottom slab and a cast-in-place layer, and their rebar layout should be considered in stages:

• Prefabricated bottom slab: The bottom rebars of the prefabricated slab should have a diameter and spacing that meet the design load-bearing capacity requirements;
• Cast-in-place layer: Surface rebars (covering the entire slab surface) and negative rebars (located at supports to resist negative bending moments) should be arranged, with span-bearing rebars arranged according to the span direction. When each span of the prefabricated bottom slab consists of multiple units, the units should be connected with cast-in-place slab joints, and reinforcing rebars (with a diameter of not less than 8mm and spacing ≤ 200mm) should be configured at the joints to ensure integrity.

Precautions: Rebar layout must strictly adhere to the design drawing requirements. Before construction, the rebar specifications, spacing, and connection methods should be verified; before pouring concrete, the thickness of the rebar protective layer (generally ≥ 15mm) should be checked to prevent rebar exposure and corrosion.