Structural Specifications for Prefabricated Slab Houses

The structural specifications for prefabricated slab houses cover multiple aspects, including structural integrity, core components, design and construction, as well as design life and safety. Details are as follows:

Structural Integrity and Foundation Inspection

For the foundation, it is necessary to check whether there are obvious settlement marks on the ground around the house, whether there is a height difference between the indoor and outdoor floors, and observe whether there are diagonal cracks at the bottom of the walls due to uneven foundation settlement. The tilt of the house should not be overlooked. Stand at a certain distance to visually inspect whether the entire house has any visible tilt, skewing, or twisting phenomena.

Special Inspection of Core Components

• Prefabricated Floor Slabs: Check for horizontal through-cracks at the bottom of the slabs or whether there are obvious cracks at the joints between slabs. Observe whether there are signs of downward bending or sinking in the middle of the floor slabs. Check the positions where the two ends of the prefabricated slabs rest on the walls for any loose concrete, debris falling off, or exposed and rusted steel bars.
• Load-Bearing Walls: Focus on checking for vertical or diagonal cracks on the load-bearing walls or whether there are cracks and downward deformation at the lintels above door and window openings. Inspect the bottom of the walls on the ground floor for severe weathering, peeling, or loosening of bricks or masonry. Determine whether the house was constructed with ring beams and structural columns. For brick-concrete prefabricated slab houses of three stories or more, if these are not installed, the overall seismic resistance and safety will be reduced.
• Node Connections: Pay attention to whether the support of the prefabricated slabs on the walls is firm and whether there are signs of looseness. The specification requires that the support length of the prefabricated slabs on brick walls should not be less than 80mm. Check for any separation or cracks at the corners and junctions of the walls.

Design and Construction Specifications

Taking prefabricated rural houses as an example, the structural system should clearly define systems such as prefabricated concrete shear wall structures, EPS module cast-in-place concrete structures, and light steel frame structures, and provide detailed design and construction specifications. Regarding material specifications, it is advisable to adapt to local conditions and use local materials, selecting green, economical, or recyclable building materials. Priority should be given to using local materials while ensuring quality, and the use of high-energy-consuming and excessively polluting materials is prohibited. In terms of construction requirements, it is preferable to have professional construction teams or trained rural individual builders with house-building capabilities organize the construction. A construction organization design and construction plan should be formulated, including component installation and node construction plans, quality management for component installation, and safety measures.

Design Life and Safety

According to the Unified Standard for Reliability Design of Building Structures (GB 50068 - 2018), as ordinary residential buildings, prefabricated slab houses typically have a design service life of 50 years. However, the actual service life is affected by factors such as building quality, usage and maintenance conditions, and environmental factors. Early prefabricated slab houses were designed with relatively low seismic standards and may not meet modern seismic requirements, especially in earthquake-prone areas, where special attention is required.