Steel bars used for construction work
(This Picture is Contributed by "Monu")
To limit cracks that may develop in reinforced concrete around mild steel bars due to stretching of bars and some lose of bond under load it is common to use deformed bars that have projecting ribs or are twisted to improve the bond with concrete. These bars are produced in sections from 6 mm to 50 mm dia.
In addition the strength of bonds of deformed bars calculated should be 40 to 80 % higher than that of plain round bars of same nominal size. And it has more tensile stress than that of plain round bars of same nominal size.
Cold twisted deformed (Ribbed or Tor Steel Bars) bars are recommended as best quality steel bars for construction work by structural Engineer.
Reinforcement bars in accordance with standard IS No. 432 part-I can be classified into following types.
1) Mild Steel Bars: Mild steel bars can be supplied in two grades
a)Mild steel bars grade-I designated as Fe 410-S or Grade 60
b) Mild steel bars grade-II designated as Fe-410-o or Grade 40
2) Medium Tensile Steel Bars designated as Fe- 540-w-ht or Grade 75
|S.No||Types of nominal size of bars||Ultimate Tensile Stress N/mm2 minimum||Yield Stress N/mm2||Elongation Percent minimum|
|1.||Mild Steel Grade I or Grade 60|
|For bars up to 20mm||410||250||23|
|For bars above 20mm upto 50 mm||410||240||23|
|2.||Mild Steel Grade-II or Grade 40|
|For bar up to 20mm||370||225||23|
|For bars above 20mm upto 50 mm||370||215||23|
|3.||Medium Tensile Steel Grade-75|
|for bars up to 16mm||540||350||20|
|for bars above 16 mm up to 32 mm||540||340||20|
|for bars above 32 mm up to 50 mm||510||330||20|
Grade II Mild steel bar are not recommended for use in structures located in earth quake zones subject to severe damage and for structures subject to dynamic loading (other than wind loading) such as railways and highways bridges.
Every lot or consignment of mild steel bars brought at the site of work should be tested in laboratory before use in the work. However for small work one can use mild steel bars on the basis of verifying tests results made by manufacturer in his own laboratory; which are available with supplier.
Some of manufacturers stamped MS bars grade with their make /name and also give certification of test and grade. On the basis of the above information you can store mild steel bars grade-wise at the site of work.
Column made of steel bars
(This Picture is Contributed by "Ahmed")
Here are details of weight per meter for various types of steel members:-
This will help us for estimated weight and cost. It will also help at the time of purchase to avoid pilferage in weight.
M S Steel round & square Bar
|Sr.No.||Dia of steel bar||Weight per meter|
||Round Bar||Square Bar|
|a|| 6 mm
|| 0.22 Kg.
|b|| 8 mm
|| 0.39 Kg
|c|| 10 mm
|| 0.62 Kg
|d|| 12 mm
|| 0.89 Kg
|| 1.13 Kg|
|| 16 mm
|| 1.58 Kg
|| 2.01 Kg|
|f|| 20 mm
|| 2.46 Kg
|| 3.14 Kg|
|g|| 25 mm
|| 3.85 Kg
|| 4.91 Kg|
|h|| 28 mm
|| 4.83 Kg
|| 6.15 Kg|
|i|| 32 mm
|| 6.31 Kg
|| 8.04 Kg|
|j|| 36 mm
|| 7.99 Kg
|| 10.17 Kg|
|k|| 40 mm
|| 9.86 Kg
|| 12.56 Kg|
|l|| 45 mm
|| 12.49 Kg
|| 15.90 Kg|
|m|| 50 mm
|| 15.41 Kg
||19.62 Kg |