What are different diameters of steel used in construction field

Steel is used extensively in construction works as it is ductile, flexible and hard. It flexes under extreme loading rather than crushing or crumbling. It binds well to concrete, has a uniform thermal expansion coefficient and is strong and relatively cost effective.

Reinforcement is required for reinforced concrete structures such as foundation or footings, slabs, lintels,beams,columns etc. 

There are different diameters used in all structures depending upon the availability and use.Diameter of the bar will vary according to the load condition.In construction field,steel quality is verified in order to select the brand of steel for all construction purposes.

Learn more-Steel quantity  per m³ 

Bars which are available in the market are 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 28 mm, 32 mm, 36 mm and 42 mm.

Steel Works 

BARS IN BEAM

In beam, we use bars having diameter greater than 12mm (depending upon loading condition)

BARS IN COLUMN

In column, we use bars having diameter greater than 12mm i.e 16mm, 20mm and 25mm (depending upon loading condition)

BARS IN SLAB

In slab,loading is less as compared to the beams,column or footing. we generally use 8mm, 10mm , 12mm diameter of bars.

BARS IN FOOTING/FOUNDATION 

A sub-structure or foundation varies in terms of loading .The diameter of steel bars are selected as per the design.

For footing we use 10 mm or more.

Bars which are available in the market are 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 28 mm, 32 mm, 36 mm and 42 mm.

Greater diameter like 64 mm and 128 mm has to be ordered specially from steel plant industries.

The table below shows sizes or diameter generally used in construction field:

 

S.no.	Description of RCC Member	Diameter/size of Reinforcement Required
1	Roof slab
	(a) One way slab	8mm dia – 70% Distribution bars – 6mm – 30%
	(b) Two way slab	8mm dia – 100%
	(c) Square slab – 4m to 6m size	10 – 12mm dia – 100%
2	Main beams above 6m	20mm, 16mm, 12mm – 80 – 85% Stirrups – 8mm – 15 – 20%
3	Column footings	10mm or 12mm
4	Grade beams with load	12mm, 16mm – 85% Stirrups –  8mm– 15%
5	Grade beams	8mm diameter – 85%, Stirrups 8mm – 15%
6	Columns	16mm, 20mm and 25mm – 90% Ties –  8mm – 10%
7	Lintel beam	12mm, 16mm dia – 85% Stirrups –  8mm – 15%
8	Sunshades	8mm dia – 75% Distribution bars – 6mm – 25%
9	Staircase waist slab	12 or 16mm dia – 80% Distribution bars 8mm dia – 15%
10	Canopy slab upto 2.0 m span	10mm dia – 80% Distribution bars – 8mm – 20%

Note:- Actual quantity of steel required can be calculated from the drawings prepared after structural design.Any particular project, needs structural drawings provided with different structural details which is recommendedto prepare BBS (bar binding schedule).

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