Construction of a Concrete Slab:
a Concrete Slab is a common structural element in modern buildings.
In many Residential and Industrial buildings a thick concrete slab supported on foundations or directly on the subsoil is used to construct the ground floor of a building.
Concrete slabs are built on the building site using formwork - a type of boxing into which the wet concrete is poured.
Plastic tipped metal are used to hold the rebar away from the bottom and sides of the form-work so that when the concrete sets it completely envelops the reinforcement.
Slabs can either be ground-bearing or suspended.
- Ground-Bearing Slab: The form-work may consist only of sidewalls pushed into the ground.
- Suspended Slab: The form-work is shaped like a tray,often supported by a temporary scaffold until the concrete sets.
Design of a Slab:
For a suspended slab, there are a number of designs to improve the strength-to-weight ratio. In all cases the top surface remains flat,and the underside is modulated with either a corrugated,ribbed or waffle design
Corrugated slabs are created when concrete is poured into a wavy metal form,this improves strength and prevents the slab from bending/sagging under its own weight.
The corrugations run across the short dimension from side to side.
Ribbed floors consisting of equally spaced ribs are usually directly supported by columns giving considerable extra strength on one direction.
Reinforced concrete footing and slab system constructed on ground consisting of a perimeter footing (edge beam) and a series of narrow internal beams (strip footings) at one metre nominal centres running each way.
The slab is to be reinforced with rebars (reinforcing bar) or better known as reinforcing steel and reinforcement steel are positioned within the formwork before the concrete is poured in.