What is Rebaring ? Types of Steel Reinforcement Bars , types of rebaring , Types of Deformed Steel Bars

What is Rebaring ?

Steel reinforcement bars or rebars are used to improve the tensile strength of the concrete, since concrete is very weak in tension, but is strong in compression. Steel is only used as rebar because elongation of steel due to high temperatures (thermal expansion coefficient) nearly equals to that of concrete.

Rebaring is the method of insertion of the Steel bars when,
there is change in design or there is some extension of the present structure.When Steel rod as per drawing has not been installed.
Rebaring technique is reinforced concrete construction is a method for proper fabrication and placement of reinforcement bar as per the design and drawing of RCC work.
2)  Need of Rebaring
The rebars are mainly provided at the junction where the formwork of structural element is closed as well as at the point where a new structural element needs to be bond with the former one.Change in the design and sudden extension in structure.Steel bars are not placed according to as per design.
Various conditions that rebaring process and equipment are changed.rebaring technique in reinforced concrete construction.Rebaring technique on a Pre-casted structure.
3) Process of rebaring in reinforced concrete construction.

The three main operations carried out in rebaring for reinforced concrete construction bars are cutting, bending, tying.
The diameter of reinforcement bars used reinforced concrete works mainly  ranges from 6 to 42 mm these reinforcement bars comes from the Steel mills in specified lengths.
So during installation the reinforcement bars must be cut into required size.

The design engineer show the details about the bar bending and related work based on which the workers proceed the work.

4) Equipments used for rebaring techniques.

The equipments that is used for Rebaring operation is developed with the time as the size of Bar is increases. large size of bars are difficult to be handled by hand operation.
The uses of chisel and hammer was an early effect is used for bar bending.

Grades of Rebar in Different Codes

Table 1: Grades of Rebar in Different Codes

American Standard (ASTM A 615) Euro Standard(DIN 488) British Standard BS4449: 1997 Indian Standard (IS: 1786)
Grade 75 (520) BST 500 S GR 460 A Grade Fe – 415, Fe – 500, Fe – 500D
Grade 80 (550) BST 500 M GR 460 B Grade Fe – 550

Types of Steel Reinforcement Bars

Major types of steel bars used in the construction are as follows,

1. Mild Steel Bar

The surface of the mild steel bars are plain and round in shape. They are available in various sizes of 6 mm to 50 mm. They are used in concrete for special purposes, such as dowels at expansion joints, where bars must slide in a metal or paper sleeve, for contraction joints in roads and runways, and for column spirals. They are easy to cut and bend without damage.

For structural buildings like bridges and other heavy structures, mild steel bar is not recommended due to no great bonding between concrete and steel, slippage and strength.

Grades in mild steel bars

1. Mild Steel Bars

  • Mild steel bars grade-I designated as Fe 410-S or Grade 60.
  • 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.

Physical Requirement of Mild Steel Bars

Table 2:Physical Requirement of Mild Steel Bars

Types of Nominal size of bar Ultimate Tensile Stress in N/mm2 Yield Stress N/mm2 Elongation Percentage min
Mild Steel Grade I or Grade 60
For Bars upto 20mm 410 250 23
For Bars above 20mm upto 50mm 410 240 23
Mild Steel Grade II or Grade 40
For Bars upto 20mm 370 225 23
For Bars above 20mm upto 50mm 370 215 23
Medium Tensile Steel Grade -75
For Bars upto 16mm 540 350 20
For Bars above 16mm upto 32mm 540 340 20
For Bars above 32mm upto 50mm 510 330 20

2. Deformed Steel Bar