Concrete Cover (Clear Cover, Nominal Cover, Effective Cover)

 

Concrete Cover Definition, Types, Formulas

What is Concrete Cover:

The concrete cover is a distance between the rebars and the outer surface of the RCC Component. The Concrete cover protects rebars (Reinforcement Steel) from environmental effects (Corrosion, Rust, Oxidation…etc).

Commonly concrete cover has 3 types, 1- Clear Cover, 2-Nominal Cover, 3-Effective Cover

1-     Clear Cover: it’s a distance between the rebars and the outer surface of the RCC member including Shear/Torsion, Ties, Stirrups, or links

      Figure 1: Clear Cover

2-     Nominal Cover: Nominal cover is the same thing as a clear cover, but this term is used by the code and it’s the dimension shown in drawings and details.

 

 3-     Effective Cover: this is the distance between the center of area of the main reinforcement and the outer surface of the RCC member including Shear/Torsion, Ties, Stirrups, or links. This is used usually for Design dimension or Calculation.

  

 

                        I.          Formula for Effective Cover = Clear cover + (Dia Stirrups/Ties/links) + ½ (Día                          Main Steel Bars)

                        II.          Effective Cover in Beam = Over all depth – Effective depth

 

Reinforcement Concrete Cover:

Footing	50 mm
Raft Foundation Top	50 mm
Raft Foundation Bottom/ Sides	50 - 75 mm
Strap Beam	50 mm
Grade Slab	20 mm
Column	40 mm
Shear Wall	25 mm
Beams	25 mm