What Does the Prefabricated Floor Slab of a House Look Like?

The prefabricated floor slab of a house is a commonly used floor component in early 20th-century construction. It belongs to engineering modules or panels and is composed of concrete prefabricated parts, which are processed and formed at a prefabrication site and then directly transported to the construction site for installation.

Production Process

In traditional processes, the production of prefabricated slabs involves first nailing a hollow mold with wooden planks. After arranging steel bars in the hollow part of the mold, cement is poured in and allowed to dry. Finally, the wooden planks are knocked off to obtain the finished product. Modern processes are more complex: workers first form a mold with steel plates and spray a release agent, then lay distribution bars and a thin concrete layer in sequence. Next, a large foam board (about 15 centimeters thick) is placed and fixed with iron hooks. Subsequently, a steel bar framework is laid on the foam board, and high-strength steel strands are threaded through. The "pre-tensioning method" is used to tighten the steel bars before pouring the second layer of concrete, and a vibrating rod is used to eliminate air bubbles. Finally, the concrete is hardened through steam curing, the steel strands are loosened, and excess steel bars are cut to complete the production of the prefabricated slab.

Structural Types

Prefabricated slabs are divided into two types: solid and hollow. The hollow structure achieves lightweighting by reducing the non-load-bearing concrete, which not only reduces material usage but also lightens the floor's self-weight, making it suitable for scenarios with low load requirements. The solid structure, on the other hand, is often used in areas with high load-bearing or seismic performance requirements due to its strong integrity.

Dimensions and Specifications

• Span: The longest prefabricated slab for residential use is 4.2 meters, and customization is required for longer spans.
• Width: The main widths are 500mm and 600mm, with common designs featuring four holes (400mm) or five holes (500mm).
• Thickness: Common thicknesses are 120mm and 150mm, which need to be selected based on load requirements.
• Length: Designed according to a 300mm modulus, such as 3000mm, 3300mm, etc. The longest ordinary slab is 4200mm, and special requirements can be customized to specifications like 3800mm and 4000mm.

Load Ratings

Prefabricated slabs are classified into different grades based on their ability to bear live loads:

• Grade I slabs: Can bear a live load of 1kN/m² and are suitable for ordinary residential buildings.
• Grade II slabs: Can bear a live load of 2kN/m² and are used in scenarios with slightly higher load requirements.
• Regulations in the Southwest Region: The minimum requirement is for Grade IV slabs, which can bear a live load of 4kN/m² to adapt to regional geological or climatic conditions.

Prefabricated slabs significantly improve construction efficiency through standardized production and modular installation. However, their design must strictly match the building's load requirements to avoid safety hazards caused by non-compliant specifications.