Calculating the quantity of steel in a structure involves determining the required amount of reinforcement for each element. Here’s a general guide:
1. Slab:
Calculate the total area of the slab, determine the design requirements for reinforcement (usually given in terms of percentage of the cross-sectional area) and multiply the area by the percentage of reinforcement to get the quantity of steel required.
2. Column:
Calculate the cross-sectional area of the column, consider the height of the column and the design requirements for reinforcement, and multiply the area by the percentage of reinforcement to find the quantity of steel.
3. Beam:
Calculate the cross-sectional area of the beam, take into account the span length and design requirements for reinforcement, multiply the area by the percentage of reinforcement to determine the quantity of steel.
4. Footing:
Determine the plan area of the footing, consider the depth of the footing and the design requirements for reinforcement, and multiply the area by the percentage of reinforcement to find the quantity of steel.
Steel is one of the most important building material used in construction, as we know concrete is good in compression but weak in tension so we use Steel bar to enhance the tensile strength of concrete that’s why steel is also known as reinforcing bar or rebar.
Steel is embedded in concrete fibre to construct footing, beam, column and slab in residential and commercial houses. Column beam and footing, it’s all are load bearing structure safely transfer all incoming load to bed of soil.
In this article we know about how to calculate quantity of steel in slab column, beam & footing. We will follow thumb rules to calculate the Steel quantity needed for RCC slab, beam, column and footing.
Thumb rules refer to any easily learned process or standard based on practical experience rather than theory, it is not strictly to accurate or reliable for every situation, it give give us quick decision at construction site.
How to calculate quantity of steel in slab, column, beam & footing
To calculate steel quantity required for RCC structure column, beam and slab, multiply the cross-sectional area by its total length by the density of steel which is 7850 kg/m3 and by percentage of steel. Total steel quantity = Area × Length × % of steel × 7850. For example, total amount of steel required for 30 m2 slab at 100 mm thickness = 30 × 0.1× 0.01×7850 = 235 kg.
Steel calculation for slab: To calculate the quantity of steel required for RCC slab, measure the Length, Width and Thickness in meter, multiply all together to get volume. Multiply 1% to volume of slab to density of steel (7,850 kg/m3) to get quantity of steel required for slab in kg.
◆ Important Link
● Unit weight of steel bars: (8mm, 10mm, 12mm, 16mm & 20mm)
Example 1
FOR SLAB
How to calculate quantity of steel required for slab
The length, width and depth of slab is 6m × 5m × 0.10m.
As per thumb Rule, the amount of steel quantity required for an RCC roof slab should be 1% of total volume of concrete slab.
Calculate volume of concrete i. e. 6m × 5m × 0.10m= 3m3:- here we have slab of 6 meter length, 5 meters width and 100mm or 4″ thick, so volume of concrete of slab = 6m × 5m × 0.10m= 3m3.
Calculate Steel quantity for slab as 1% of volume of concrete = 0.01× 7850 kg/m3× 3 m3 = 236 kg of steel.
How much steel required for RCC slab
As per thumb rule, the amount of steel required for RCC roof slab is about 1% of total volume of concrete slab. For example, steel required for a 100 sq ft and 4 inch thick slab = (100×4/12)/35.32 × 0.01 × 7850 = 75 kg.
How to calculate quantity of steel required for column
Steel calculation for column: To calculate the quantity of steel required for column, measure the Length, Width and Thickness of column in meter, multiply all together to get volume. Multiply 2.5% to volume of column to density of steel (7850 kg/m3) to get quantity of steel required for column in kg.
Example 2
FOR COLUMN
How to calculate quantity of steel for 10 column
The length, width and height of column is 0.30m × 0.30m × 4.5m.
As per Thumb Rule Steel quantity required for RCC column should be 2.5% of total volume of concrete.
Calculate volume of concrete as 0.30m × 0.30m × 4.5m × 10 = 4.05m3:- here we have 10 column of 0.30 meter length, 5 meters width and 4.5 meters in height, so volume of concrete of 10 column = 0.30m × 0.30m × 4.5m × 10 = 4.05m3.
Calculate Steel quantity for column as 2.5% of volume of concrete = 0.025× 7850× 4.05= 795 kg
The amount of steel required for 10 pillar (RCC column) measuring 1 x 1 foot (12″ x 12″) and 10 feet high is approximately 795 kg. Typically, 10 full-size residential RCC column (pillar) requires 795 kilograms of steel.
How much steel required for 1 pillar (column)
To calculate the quantity of steel for 1 pillar (column) having the length, width and height as 0.3m x 0.3m x 3m. As per the thumb rule, steel quantity required for RCC column should be 2.5% of the total volume of concrete.
Calculate the volume of concrete by multiplying all the three dimensions of the column as 0.3m x 0.3m x 2m = 0.27m3
To calculate the steel quantity for 1 pillar (column) as 2.5% of volume of concrete = 0.025 x 7,850 x 0.27 = 53 kg.
The amount of steel required for 1 pillar (RCC column) measuring 1 x 1 foot (12″ x 12″) and 10 feet high is approximately 53 kg. Typically, 1 full-size residential RCC column (pillar) requires 53 kilograms of steel.
Example 3
IN BEAM
How to calculate quantity of steel for beam
Steel calculation for beam: To calculate the quantity of steel required for rcc beam, measure the Length, Width and Thickness of beam in meter, multiply all together to get volume. Multiply 2% to volume of beam to density of steel (7850 kg/m3) to get quantity of steel required for beam in kg.
The length, width and thickness of beam is 100m × 0.230m × 0.230m.
As per Thumb Rule Steel quantity required in RCC beam should be 2% of total volume of concrete.
● Calculate volume of concrete as 100m × 0.230m × 0.230m = 5.29m3:- here we have total length of beam is 100m, 230mm width and 230mm in thickness, so volume of concrete for 100m beam = 0.230m × 0.230m × 100m = 5.29m3.
● Calculate Steel quantity in beam as 2% of volume of concrete = 0.02× 7850× 5.29= 830 kg:- according to using Thumb Rule Steel quantity required in RCC beam should be 2% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in beam = 0.02× 7850× 5.29 = 830 kg.
How to calculate quantity of steel for footing
Steel calculation for footing: To calculate the quantity of steel needed for rcc footing, measure the Length, Width and Thickness of footing in meter, multiply all together to get volume of beam in cubic meter. Multiply 0.5% to volume of concrete footing to density of steel (7850 kg/m3) to get quantity of steel required for footing in kg.
Example 4
IN FOOTING
How to calculate quantity of steel in footing having the length, width and thickness of one footing is 3m × 3m × 0.3m.
As per Thumb Rule Steel quantity required in footing should be 0.5% of total volume of concrete.
● Calculate volume of concrete as 3m × 3m × 0.3m = 2.7m3:- here we have length of footing is 3m, 3mm width and 300mm in thickness, so volume of concrete for one footing = 3m × 3m × 0.3m = 2.7m3.
● Calculate Steel quantity in footing as 0.5% of volume of concrete = 0.005× 7850× 2.7= 106 kg:- according to using Thumb Rule Steel quantity required in footing should be 0.5% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in footing = 0.005× 7850× 2.7 = 106 kg.
How much quantity of steel required for slab, beam, column and footing per 1m3 of concrete
Example 1
IN SLAB
How much quantity of steel required in slab per 1m3 of concrete
● As given volume of concrete 1m3 of slab
● Calculate Steel quantity in slab as 1% of volume of concrete = 0.01× 7850× 1= 78.50kg:- according to using Thumb Rule Steel quantity required for RCC slab should be 1% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in 1m3 of concrete slab = 0.01× 7850× 1= 78.50kg, so, therefore 78.50kg of Steel are required for slab per 1m3 of concrete.
The amount of steel required for 1 m3 of RCC slab is about 78.50 kg. A typical RCC roof slab requires 78.50 kg of steel per m3 (cubic meter).
Example 2
FOR COLUMN
How much quantity of steel required for column per 1m3 concrete.
● As given volume of concrete 1m3 of column
● Calculate Steel quantity required for column as 2.5% of volume of concrete = 0.025× 7850× 1= 196kg:- according to using Thumb Rule Steel quantity required for RCC column should be 2.5% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in 1m3 of concrete column = 0.025× 7850× 1= 196kg, so, therefore 196kg of Steel are required for column per 1m3 of concrete.
The amount of steel required for 1 m3 of RCC column is about 196 kg. A typical RCC column requires 196 kg of steel per m3 (cubic meter).
Example 3
FOR BEAM
How much quantity of steel required for beam per 1m3 concrete.
● As given volume of concrete 1m3 of beam
● Calculate Steel quantity required for beam as 2% of volume of concrete = 0.02× 7850× 1= 157kg:- according to using Thumb Rule Steel quantity required for RCC beam should be 2% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in 1m3 of concrete beam = 0.02× 7850× 1= 157kg, so, therefore 157kg of Steel are required for beam per 1m3 of concrete.
The amount of steel required for 1 m3 of RCC beam is about 157 kg. A typical RCC beam requires 157 kg of steel per m3 (cubic meter).
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Example 4
FOR FOOTING
How much quantity of steel required for footing per 1m3 concrete.
● As given volume of concrete 1m3 of footing
● Calculate Steel quantity required for footing as 0.5% of volume of concrete = 0.005× 7850× 1= 39.25kg:- according to using Thumb Rule Steel quantity required for RCC footing should be 0.5% of total volume of concrete, here steel density = 7850 kg/m3, so quantity of steel in 1m3 of concrete footing = 0.005× 7850× 1= 39.25kg, so, therefore 39.25kg of Steel are required for footing per 1m3 of concrete.
The amount of steel required for 1 m3 of footing is about 40 kg. A typical RCC footing requires 40 kg of steel per m3 (cubic meter).
Conclusion:
To calculate the quantity of steel required for rcc structure, multiply the Length, Width and Thickness in meter to get volume of concrete in m3. Multiply 1% to volume of concrete slab to density of steel (7850 kg/m3) to get quantity of steel required for slab in kg.