Specification for Layout of Prefabricated Concrete Houses

The specification for the layout of prefabricated concrete houses requires comprehensive consideration from multiple aspects such as design, structure, connections, layout, and precautions to ensure safety, functionality, and compliance.

1. Pre-design Conditions and Determination of Basic Parameters
It is necessary to consider local climate, geological conditions, and building purposes to define parameters such as seismic fortification intensity, basic wind pressure, and snow load, ensuring that the structure can withstand environmental loads. Additionally, standardize building modules (usually with 300 millimeters as the basic unit), regulate component dimensions, reduce the variety of molds, enhance production efficiency, and lower costs. For example, window and door openings, as well as wall thickness, should be designed according to the module to avoid on-site cutting waste.

2. Selection of Structural System and Disassembly of Prefabricated Components

• Structural System: Preferably use assembled monolithic concrete frame structures or frame-shear wall structures. For buildings up to three stories, a pure frame structure is recommended to simplify node connections; for high-rise buildings, additional shear walls are needed to enhance lateral resistance.
• Component Disassembly: Columns, beams, slabs, and other components should be fully prefabricated, with node areas (such as beam-column joints) formed into a whole through post-poured concrete. During disassembly, control the weight of individual components (usually not exceeding 5 tons) and dimensions (to fit transportation vehicles and lifting equipment) to avoid construction difficulties caused by exceeding limits.

3. Node Connection Design
Node connections are crucial for ensuring structural safety:

• Column-to-Column: Use sleeve grouting connections, filling the gap between the metal sleeve and reinforcing bars with high-strength grout to achieve equal-strength connections.
• Beam-to-Column: Use a combination of a pre-embedded steel plate (known as a 'cow support plate') and post-poured concrete to ensure the node's flexural and shear resistance.
• Slab-to-Beam: Reserve U-shaped reinforcing bars (known as 'beard bars') at the slab end to extend into the beam-side post-pouring zone, transferring loads through reinforcing bar anchoring.
  All connections must undergo finite element analysis to verify strength and full-scale testing in the factory to ensure that the node's load-bearing capacity is not lower than that of the components themselves.

4. Layout Design Examples

• Compact Type (Approximately 80㎡): Horizontal layout with the master bedroom and secondary bedroom on the left, the living room in the middle, and an integrated dining and kitchen space on the right, suitable for small families or single occupants.
• Comfortable Type (Approximately 100㎡): Vertical layout with a front yard for greenery and the house built at the back. The living room is in the middle, with the master and secondary bedrooms on either side, and the kitchen, dining area, and a third bedroom at the back, balancing functionality and privacy.

5. Key Precautions

• Construction Permit Process: It is necessary to apply for a temporary building permit from the local housing and construction department. For rural homesteads, complete the land rights confirmation procedures to avoid illegal construction.
• Material Selection: It is recommended that the thickness of prefabricated slabs be between 12-15 cm, with a reinforcing bar ratio of not less than 0.2% to ensure structural durability.
• Drainage and Damp Proofing: Create a 5% slope on the yard ground for drainage and raise the house foundation by 30 cm to prevent rainwater backflow and ground moisture erosion.