CLEAR COVER FOR DIFFERENT R.C.C. MEMBERS

What Is Clear Cover (or) Cover in Concrete?

The clear cover (or) Cover in RCC, is the distance between the exposed concrete surface (without plaster and other finishes) to the nearest surface of the reinforcement bar i.e., Steel rod.

Mostly, it is known as "clear cover" or "minimum concrete cover" in general terms on a construction site.

Why clear cover is important?

Cover is provided to protect the reinforcing bar (rebar) from corrosion due to weather and fire. If we don't leave a cover, then the reinforcing bar will stick to the surface of the shuttering and cause rust in the bar after we casting the column or beam and also damage the strength of the column or beam.

For example, in the case of fire in a building, the metal begins to melt and lose its strength. Therefore, the clear cover acts as an insulator and prevents from melting.

This gives more strength to the bars, reduces the chances of slipping and also increases the durability of the bars. This provides adequate embedding for the reinforcing bars to withstand stress without loss of grip.

How to Define Nominal Cover

As per IS 456(Clause 26.4.1), the term clear cover has been replaced by the term Nominal cover.

The nominal cover is the distance between the exposed concrete surface to nearest reinforcement bar ( it can be any bar I.e., main bar, longitudinal bar and even links or stirrups).

What Is Effective Cover in Concrete?

The Effective cover is the distance measured betweenthe exposed concrete surface (without plaster and other finishes) to the centre of the area ( centroid ) of reinforcement, i.e., tension or compression reinforcement. 

Effective cover = overall depth – effective depth.    (Or). 

Effective cover = Clear cover + Diameter of Stirrup + (Diameter of main reinforcement bar ÷ 2).

Member	Clear cover (Normal Conditions)	wet climatic environment or sea side location
Foundation	75 mm
Raft Foundation	Top = 50 mm Bottom = 75 mm Sides = 75 mm
Strap Beam	50 mm
Beam	25 mm	35 to 40 mm
Column	40 mm	50 mm
Flat Slab	20 mm
Slab	15 mm

Rod weight per bundle: 8mm, 10mm, 12mm, 16mm, 20mm & 25mm steel bar

          Rod or steel bar is also known as Rebar, it is the short form of reinforcing bar. It is steel Rod or Steel wire provided as tension bar in concrete structure, used in  reinforced concrete structure  like column, beam and slab of house construction. It is used to increase the tensile strength of concrete structure.

Reinforcing bar/rebar surface is often deformed with ribs to promote a better bonding with the concrete material and reduce the risk of slippage.

In this article we will briefly explain the rod weight per bundle:

Let us first know about length of one piece of rod or steel bar, in India full length of one Steel bar or rod which are used in construction are available in 12 meter or approximately 40 feet long. TMT rebars or steel rods are supplied in U bent or straight rods.

TMT bars per bundle: 

TMT SIZE (mm)	RODS PER BUNDLE
6	20 No / Length
8	10 No / Length
10	8 No / Length
12	5 No / Length
16	3 No / Length
20	2 No / Length
25	1 No / Length

Rod weight per bundle:-   Generally we can calculate the weight of rod or steel bar in kg per bundle of full length of 12 meters using the formula D^2L/162 × number of pieces.

Example: If we want to calculate the weight of 6mm  rod bundle we will calculate using the formula D^2L/162 × number of pieces.

 = {(6X6X12)/162}X20 

 = 53.33 kg/Bundle

Weight Chart of TMT Bars per Bundle:

TMT Steel Bar Size in mm	Length of TMT Steel Bar (Meter)	TMT Steel Bar pieces per bundle (No.s)	Total Weight of TMT Steel Bar bundle (Kg)
6	12	20	53.33 Kg
8	12	10	47.4 Kg
10	12	7	51.85 Kg
12	12	5	53.34 Kg
16	12	3	56.89 Kg
20	12	2	59.26 Kg
25	12	1	46.29 Kg
28	12	1	58.07 Kg
32	12	1	75.85 Kg