A hollow-core slab floor is a prefabricated concrete floor element in which hollow cores (tubes) run along its length. These voids reduce the weight of the floor without significantly reducing its load-bearing capacity. The planks are made from prestressed concrete in a factory and laid side by side on site with a crane.
Build-up and properties
- Prestressed — the planks contain prestressed steel strands that make the floor strong over large spans
- Lighter than a solid floor — thanks to the hollow cores, which makes transport and installation easier
- Standard width — the planks are typically about 1.20 metres wide; the thickness varies roughly from 150 to 400 mm, depending on the span and load
- Large span — depending on the thickness, spans of up to about 16 to 20 metres are possible
Application
Hollow-core slab floors are widely used in:
- Housing — as an intermediate floor, especially in apartments
- Commercial construction — offices, schools, car parks, and industrial halls
- Floors that must remain free of intermediate supports, thanks to the large span
Advantages and processing
The main advantage is fast installation: the planks are laid directly onto the load-bearing walls or beams, after which the joints between the planks are grouted with mortar. Often a thin, reinforced structural topping of concrete is cast over the top to create a composite, stiff floor diaphragm. Services are concealed within the cores, the topping, or a screed.
Related terms
- Precast
- Prestressed concrete
- Structural topping
- Span
- Lattice-girder floor
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