Contents
 What are steel bars?
 What are the types of steel bars?
 What is the unit weight of steel?
 What is the formula of weight of steel?
 What is the formula of weight of steel bars?
 How to calculate weight of steel bars in feet or foot?
 How to calculate unit weight of steel per meter?
 What is the unit weight of steel in kg/m3?
 What is the standard weight of steel?
 What is the weight of TMT steel bars?
 How to calculate weight of steel bar of 8mm diameter?
What are steel bars?
Steel bars are the core components of the construction industry. Steel bars are also known as reinforcing bars or reinforcing steel. As we know, plain concrete is weak in tension and strong in compression. So, Steel bars are used for the reinforcement of concrete structures to strengthen the structure under the tension loading. Steel bars are nothing but bars of steel available in different shapes, sizes, and grades of steel. Steel reinforcement is the steel bars that are used in plain concrete to make it reinforced concrete. Steel reinforcement is generally known as “rebar”.
What are the types of steel bars?
There are majorly 5 different types of steel bars which are used in construction industries which are as follows:
#1 Mild steel plain bars
Mild steel plain bars are the oldest types of bars used in construction industry. As its name suggest, these bars are plain from outside i.e. smooth round surface as compared to deformed bars. These types of bars are having very less tensile strength. They are generally used in small construction projects where less tensile strength is required.
#2 Hot rolled deformed bars
As name suggest, these bars are made up of Hot rolling process in which bars are made up of deformed shape i.e. ribs on the surface which ultimately helps in making bond with the concrete. These are the most common bars used in reinforcement of structures now days. They have a high tensile strength of 60000psi.
#3 TMT bars
TMT stands for “Thermo Mechanical Treatment”, now a day’s Fe 500 and Fe 500D are the most used TMT bars in civil construction purposes.TMT steel is having various properties such as anticorrosion, good in earthquake resistant , light in weight, and is easy to assemble.
#4 Cold worked steel bars
As the name suggest, these bars are made up of a cold working process in which bars are first processed through hot rolled and then undergo cold rolling. These types of bars undergo twisting and turning at room temperature which reduces the ductility of the bars.
#5 Prestressing steel bars
Prestressing steel bars are the reinforcement bars used in the form of strands or tendons. Numbers of strands are used in concrete to perform the prestressing action in the structure. The strands are made up of bundles of wire such as 2 or 3 or 7 wire strands. The wires used in the prestressing are coldformed wires. They have great tensile strength of 250000270000psi.
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What is the unit weight of steel?
The unit weight/specific weight of steel or weight density of steel can be expressed as the ratio of weight of steel to it’s per unit volume. The unit weight of reinforcing steel or density of steel is about 7850 kg/m3 or 78.5kN/m3 or 490lbs/ft3.
What is the formula of weight of steel?
The formula to calculate the Steel weight = volume * density
Steel weight =cross sectional area of bar * length * density
= breadth * length * thickness * density (for rectangular bars)
= [π (diameter) ^2/4] * length * density (for round bars)
We know that, the value of π= 3.14,
Density of mild steel is about 7850kg/m3,
‘D’ Diameter of bar is measured in ‘mm’,
‘L’ Length of bar is measured in ‘meter’
1mm=1/1000 m
Therefore, weight ‘W’= [3.14 (diameter) ^2/ (4*1000*1000)] * length * 7850
W= (diameter) ^2* length *0.00616225
W= [(diameter) ^2* length]/162
W=D*D*L/162 kg/m
What is the formula of weight of steel bars?
Reinforcement bars are generally in round shapes of different sizes. E.g. 6mm, 8mm, and so on.
Unit weight of reinforcement bars = volume* density
= crosssectional area* length* density
= [π (diameter of bar) ^2/4] * length of bar * density of steel.
We know that, the value of π= 3.14,
Density of mild steel is about 7850kg/m3,
‘D’ Diameter of bar is measured in ‘mm’,
‘L’ Length of bar is measured in ‘meter’
Therefore, weight ‘W’= [3.14 (diameter) ^2/ (4*1000*1000)] * length * 7850
W= (diameter) ^2* length *0.00616225
W= [(diameter) ^2* length]/162
W=D*D*L/162 kg/m
How to calculate weight of steel bars in feet or foot?
Formula used to calculate the unit weight of steel per unit length is
W=D*D*L/533 kg/ft (unit weight of steel bar in kilogram per feet)
W=D*D*L/162 kg/m (unit weight of steel bar in kilogram per meter)
Diameter of bar (mm) 
Unit weight of steel 

Kg/m  Kg/ft  
8mm  0.395kg  0.120kg 
10mm  0.617kg  0.188kg 
How to calculate unit weight of steel per meter?
Unit weight of reinforcement bars = volume* density
= cross sectional area* length* density
= [π (diameter of bar) ^2/4] * length of bar * density of steel.
Therefore, weight ‘W’= [3.14 (diameter) ^2/ (4*1000*1000)] * length * 7850
W= (diameter) ^2* length *0.00616225
W= [(diameter) ^2* length]/162
W=D*D*L/162 kg/m
For example, unit weight of 10mm bar of 1m length
W=D*D*L/162 kg/m
W=10*10*1/162 kg/m
W=0.61728 kg/m
What is the unit weight of steel in kg/m3?
The unit weight/specific weight of steel or weight density of steel can be expressed as the ratio of weight of steel to its per unit volume.
What is the standard weight of steel?
The standard weight /density of steel are 7850 kg/m3 or 78.5kN/m3 or 490lbs/ft3.
What is the weight of TMT steel bars?
The weight of 1TMT bar can be calculated as follows:
W=D*D*L/162
Whereas,
W= Weight of bar (kg)
D=Diameter of bar (mm)
L=Length of bar (meters), generally the length of 1TMT bar is 12 meter
For example, lets us calculate for 8mm TMT bar
W=8*8*12/162
W=4.74 kg
Hence we can say that, Weight of the 8 mm diameter TMT bar is 4.74 kg.
How to calculate weight of steel bar of 8mm diameter?
There are different steel diameters which are used for the reinforcement of structure such as 8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 32mm, and 40mm.
For calculating, the unit weight of the steel bar, assume the length of the bar is 1m
The unit weight of 8mm diameter steel bar
=D*D/162
=8*8/162
=64/162
=0.395 kg/m
Hence, the unit weight of the 8mm diameter steel bar is 0.395kg/m or we can say that the 8mm steel bar weight per meter is 0.395 kg.
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