Concrete slab

Suspended slab under construction, with the formwork still in place
Suspended slab formwork and rebar in place, ready for concrete pour.

A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel-reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving (see below).[1][2]

In many domestic and industrial buildings, a thick concrete slab supported on foundations or directly on the subsoil, is used to construct the ground floor. These slabs are generally classified as ground-bearing or suspended. A slab is ground-bearing if it rests directly on the foundation, otherwise the slab is suspended.[3] For multi-story buildings, there are several common slab designs (see § Design for more types):

  • Beam and block, also referred to as rib and block, is mostly used in residential and industrial applications. This slab type is made up of pre-stressed beams and hollow blocks and are temporarily propped until set, typically after 21 days.[4]
  • A hollow core slab which is precast and installed on site with a crane
  • In high rise buildings and skyscrapers, thinner, pre-cast concrete slabs are slung between the steel frames to form the floors and ceilings on each level. Cast in-situ slabs are used in high rise buildings and large shopping complexes as well as houses. These in-situ slabs are cast on site using shutters and reinforced steel.

On technical drawings, reinforced concrete slabs are often abbreviated to "r.c.c. slab" or simply "r.c.". Calculations and drawings are often done by structural engineers in CAD software.

  1. ^ Garber, G. Design and Construction of Concrete Floors. 2nd ed. Amsterdam: Butterworth-Heinemann, 2006. 47. Print.
  2. ^ Duncan, Chester I. Soils and Foundations for Architects and Engineers. New York: Van Nostrand Reinhold, 1992. 299. Print.
  3. ^ "Ground slabs - Introduction". www.dlsweb.rmit.edu.au. Archived from the original on 2019-11-18. Retrieved 2017-12-07.
  4. ^ "What is a rib and block slab?". www.royalconcreteslabs.co.za. Royal concrete slabs.