GENERAL GUIDLINES FOR REINFORCEMENT BAR

REINFORCEMENT BAR DETAIL GUIDELINE

The material added to concrete for resist the tension produce within the internal fibres of structure during loading is called steel bars or reinforcement bars. These bar installed in the tension zone to strengthen the structure and avoid to produces cracks during loading. when the bars is also use in compression zone the strength increases up to 20%, if deformed bars is used then strength will increase up to 40%.

TYPES OF REINFORCEMENT 

1. Mild Steel Plain Bars : A mild steel bar made up of with out surface deformation is called mild steel plain bar.

IS: 432 (part 1) Specification :

• In this categories, for bar up to 20 mm diameter, characteristic yield strength is 250 N/mm2.

• For bar over 20 mm diameter, characteristic yield strength is 240 N/mm2. 

• In tension, bar up to 20 mm diameter, the permissible stresses 140 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 130 N/mm2 is taken into account  

• Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account. 

• Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 140 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm,  permissible stresses 130 N/mm2 for bar diameter over 20 mm is consider.

2. Mild Steel Hot Rolled Deformed Bars : A mild steel bar made up of surface deformation is called mild steel deformed bar.

IS: 1139 Specification :

• In this categories, for bar up to 20 mm diameter, characteristic yield strength is 250 N/mm2.

• For bar over 20 mm diameter, characteristic yield strength is 240 N/mm2. 

• In tension, bar up to 20 mm diameter, the permissible stresses 140 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 130 N/mm2 is taken into account  

• Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account. 

• Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 140 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm,  permissible stresses 130 N/mm2 for bar diameter over 20 mm is consider.

3. Medium Tensile Steel Plain Bars : This type of bars shows a medium characteristic yield strength.

IS: 432 (part 1) Specification :

• In this categories, for bar up to 20 mm diameter, characteristic yield strength is 350 N/mm2.

• For bar between 20 mm to 40 mm diameter, characteristic yield strength is 340 N/mm2. 

• In tension, bar for any diameter, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2

• Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account for any diameter. 

• Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2.

4. Medium Tensile Steel Deformed Bars : 

IS: 432 (part 1) Specification :

• In this categories, for bar up to 20 mm diameter, characteristic yield strength is 350 N/mm2.

• For bar between 20 mm to 40 mm diameter, characteristic yield strength is 340 N/mm2. 

• For bar over 40 mm diameter, characteristic yield strength is 320 N/mm2
• In tension, bar for any diameter, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2

• Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account for any diameter. 

• Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2.

5. High Yield Strength Steel Deformed Bars : HYSD is the high yield strength deformed bars have ribs on the surface and this increases the bond strength at least by 40%.

IS: 1139 Specification :

• In this categories, bar for all size diameter, characteristic yield strength is 415 N/mm2.

• In tension, bar up to 20 mm diameter, the permissible stresses 230 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 230 N/mm2 is taken into account  

• Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 190 N/mm2 in steel reinforcement is taken into account. 

• Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 190 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm,  permissible stresses 190 N/mm2 for bar over 20 mm diameter is consider.