What is the Prefabricated Floor Slab of a House?
Prefabricated floor slabs for houses are commonly used floor components in early 20th-century architecture. They are a type of prefabricated concrete component, produced through standardized factory manufacturing and then transported to the site for installation.
Production Process and Structural Types
Prefabricated slabs are produced using two main processes: traditional production and new production:
- Traditional Process: A hollow mold is made using wooden planks. Reinforcing steel bars are placed inside, and cement is poured. After solidification, the wooden planks are knocked out to form a hollow structure.
- New Process: A steel mold is used. First, a first layer of steel reinforcement framework is laid, and a 4-centimeter-thick layer of concrete is poured. A 15-centimeter-thick foam board (for lightweighting) is then embedded and its shape is fixed. Subsequently, a second layer of steel reinforcement framework is laid, and high-strength steel strands are threaded through and tensioned to their ultimate strength using the "pre-tensioning method." A second layer of concrete is then poured. After solidification, air is expelled using a vibrating rod, and steam curing is carried out for 4 hours. Finally, excess steel bars are cut to complete the production.
Structurally, prefabricated slabs are divided into two types: solid and hollow. The hollow structure achieves lightweighting by reducing the non-load-bearing concrete while maintaining load-bearing capacity, making it a common optimization design in early architecture.
Specifications and Parameters
The dimensions of prefabricated slabs are designed to meet architectural requirements, with the main parameters as follows:
- Span: The longest span for residential use is 4.2 meters; customization is required for longer spans.
- Width: Mainly 500mm and 600mm, with common designs featuring four holes (400mm) and five holes (500mm).
- Thickness: Commonly 120mm and 150mm, selected based on load requirements.
- Length: Increments of 300mm, such as 3000mm, 3300mm, etc. The longest standard slab is 4200mm, and custom lengths such as 3800mm and 4000mm are available for special needs.
Application Scenarios and Current Status
Prefabricated slabs were widely used in early applications such as low-rise residential floor slabs, highway ditch covers, and roof insulation layers. Their advantages lie in standardized production and high construction efficiency, but they have drawbacks such as poor integrity and weak seismic performance. With the development of construction technology, modern houses have generally adopted frame structures or reinforced concrete cast-in-place structures, enhancing structural safety and durability through integral pouring. Prefabricated slabs have gradually exited the mainstream construction market and are now only retained in temporary facilities or specific projects.
