Requirements for Reinforcement Installation in Prefabricated Houses

The installation of reinforcement in prefabricated houses should adhere to the following requirements:

I. Load and Span Adaptation
For conventional residential buildings, the live load is approximately 2 kN/m², and the dead load (including the self-weight of the slab) is about 4 kN/m². The total design load should be calculated as 6-8 kN/m². In terms of span adaptation, for medium spans (e.g., 5.2 meters), double-layer bidirectional reinforcement is required: main reinforcement (load-bearing bars) should preferably use HRB400-grade deformed steel bars with a diameter of 10-12 mm and a spacing of 100-150 mm; distribution bars can be 8-10 mm in diameter with a spacing of 150-200 mm.

II. Relationship Between Prefabricated Slab Thickness and Reinforcement Ratio
For slabs with a thickness of 8-10 cm, the reinforcement ratio should be ≥0.2%. For example, an 8 cm prefabricated slab using HRB400 steel mesh can meet the flexural strength requirements. Radiating bars or additional negative moment bars should be added at the corners of the slab to prevent cracking. HRB400 coiled wire rods (Φ8-Φ12) from Shaanxi Hengshunfa are suitable for processing stirrups and reinforcing bars.

III. Selection of Reinforcement Diameter
The diameter should be determined based on the design drawings and slab dimensions. The diameter of reinforcement at the connection between beams and slabs should be greater than that of the reinforcement within the slab. Common diameters include 8, 10, 12, 16, and 20 mm.

IV. Reinforcement Arrangement at Beam-Slab Connections
Reinforcement at the connection between prefabricated slabs and beams should be confined within the connection width and arranged using the reinforcement wrapping method. Reinforcement at the junction of longitudinal beams and slabs should be bent towards the beam and arranged along the length of the beam to enhance connectivity.

V. Arrangement of Reinforcement Mesh in Slabs
The reinforcement mesh enhances flexural strength through wrapped reinforcement loops and should be evenly distributed according to the slab dimensions and design drawings. Avoid excessive spacing or localized concentration of reinforcement, which can affect overall stability.

VI. Arrangement of Reinforcement Outside Slabs
Reinforcement bridges should be installed at the outer edges of slabs, with a width greater than the diameter of a single reinforcement bar, and arranged as parallel as possible to improve load-bearing capacity.

VII. Arrangement of Inclined Reinforcement
When the slab length exceeds the design allowance, 45° inclined reinforcement should be installed at the ends to enhance load-bearing capacity.

VIII. Construction Requirements

1. Reinforcement must meet structural calculation requirements.
2. Ordinary reinforcement should preferably use HRB400-grade seismic reinforcement; for lifting rings with a diameter ≤14 mm, HPB300 reinforcement can be used, and for those >14 mm, Q235B round steel should be used.
3. For frames and diagonal bracing members with seismic grades I, II, and III, the main load-bearing reinforcement must use reinforcement with the “E” designation and meet the following requirements: the ratio of the measured tensile strength to the measured yield strength should be ≥1.25; the ratio of the measured yield strength to the standard value should be ≤1.3; and the total elongation under maximum tensile force should be ≥9%.