Foundation for Prefabricated Panel Houses

When constructing foundations for prefabricated panel houses, the prefabricated panels removed from old houses can be used for foundation bedding or as non-removable formwork, but a comprehensive design must be carried out based on geological conditions, the number of house floors, and seismic requirements. The specific plans are as follows:

1. Application in Strip Foundation Bedding

If a strip foundation is adopted, the prefabricated panels can be cut into short sections (for example, when the excavation width of the foundation trench for a two- to three-story house is 80-100 centimeters). The direction of the steel bars should be perpendicular to the strip foundation to enhance the transverse shear resistance. During construction, the foundation trench should be compacted and leveled first. Then, the short prefabricated panels should be laid horizontally, followed by pouring a 10-centimeter concrete bedding layer. After that, the foundation steel bars should be laid, the concrete foundation should be poured, and finally, brickwork should be carried out at the bottom and the ground beam should be completed. This method can utilize prefabricated panels to reduce the amount of concrete used, but it is necessary to ensure that the size of the cut prefabricated panels matches the foundation trench to avoid local stress concentration.

2. Damp-proof Design of the Elevated Floor

The prefabricated panels can be fully laid at the bottom of the foundation to form an elevated floor. It is recommended that the elevation height be 1 meter, and a 30-50 centimeter cavity should be left to block the rise of underground moisture. Compared with directly laying a damp-proof membrane, the damp-proof effect of the elevated floor is more durable, but the following points should be noted:

• Full-laying requirements: Avoid local suspension that may lead to uneven stress distribution;
• Height specifications: A height of 1 meter can balance damp-proofing and construction convenience. A lower height will affect the effect, while a higher height will increase costs;
• Ventilation design: Ventilation openings can be reserved on the side walls of the elevated floor to accelerate the discharge of moisture.

3. Structural Reinforcement for Multi-story Houses

If prefabricated panels are used to build houses with three or more floors, the foundation must be placed on solid soil layers. The size of the red-brick foundation should be adjusted according to the geological conditions (for example, the foundation should be widened to 73 centimeters in soft soil areas), and reinforcement measures such as ground beams, ring beams, and structural columns should be added:

• In non-seismic zones: The structure can be simplified, but cross beams should be added in the middle of the rooms to disperse the pressure from the prefabricated panels;
• In seismic zones: Design should strictly follow seismic codes to ensure that the prefabricated panels are firmly connected to the walls, beams, and columns to prevent detachment during earthquakes.

4. Construction Safety Precautions

• Quality inspection: The old prefabricated panels should be free of cracks, steel bar corrosion, and other defects; otherwise, their load-bearing capacity may be reduced;
• Installation specifications: The gaps between the prefabricated panels should be filled with concrete to avoid single-point stress;
• Comprehensive evaluation: The construction plan should be formulated based on the geological report, economic capacity, and seismic requirements to avoid potential safety hazards caused by blindly simplifying the structure.

Summary: The reuse of prefabricated panels can reduce costs, but it is necessary to strictly follow the principles of structural safety. It is recommended that a professional engineer design the construction plan according to the on-site conditions.