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BAR BENDING SCHEDULE OF FOOTING

Detailed RCC Footing Reinforcement Calculator for Civil Engineering Projects

Introduction

Bar Bending Schedule (BBS) is a detailed tabular representation of reinforcement bars used in reinforced concrete structures.

• It helps in accurate estimation of steel quantity.
• Reduces material wastage.
• Improves construction planning.
• Provides accurate cutting length of reinforcement.
• Helps site engineers during bar cutting and placement.
• Ensures proper anchorage and structural safety.

Footing Reinforcement Plan & Section

Explanation of Figure

• Upper figure represents footing reinforcement plan.
• Horizontal bars represent reinforcement in one direction.
• Vertical bars represent reinforcement in perpendicular direction.
• Bars are placed orthogonally to resist bending moments in both directions.
• Bottom figure represents sectional elevation of footing.
• Bottom reinforcement is provided because tensile stresses develop at bottom face due to upward soil pressure.
• L-bends are provided at reinforcement ends for anchorage.
• Clear cover protects reinforcement from corrosion and environmental exposure.
• All reinforcement calculations are performed along centerline dimensions.
• Proper reinforcement detailing improves structural safety, durability, and crack resistance.

Engineering Explanation

Why Reinforcement is Provided?

• Concrete is weak in tension but strong in compression.
• Steel reinforcement resists tensile stresses.
• Reinforcement controls cracking.
• Bars distribute structural loads uniformly to soil.
• Anchorage bends improve bond between steel and concrete.

Importance of Clear Cover

• Protects reinforcement from corrosion.
• Improves fire resistance.
• Provides durability.
• Ensures proper compaction of concrete.

Clear Bar Length = Overall Length − 2 × Cover

Why Bend Deduction is Required?

When reinforcement bars are bent, actual steel length shortens because bending occurs around a curved radius.

One 90° Bend Deduction = 2D

Two 90° Bend Deduction = 4D

Important Formula

No. of Bars = [(Length − 2×Cover) ÷ Spacing] + 1

• Spacing is measured center-to-center.
• One additional bar is added for edge reinforcement.
• Values are rounded upward.

Cutting Length = (Length − 2×Cover) + 2(L Bend) − 4D

• L Bend = Footing Depth − 2×Cover
• Two 90° bends are considered.
• Total bend deduction = 4D.

Dynamic Footing BBS Calculator

Footing Length X (mm)

Footing Width Y (mm)

Footing Depth (mm)

Clear Cover (mm)

Bar Diameter (mm)

Bar Spacing (mm)

Calculation Result

Standard Bend Deduction Table

Bend Angle	Bend Deduction
45°	1D
90°	2D
135°	3D
180°	4D

Practical Site Engineering Notes

• Always check structural drawing before preparing BBS.
• Provide proper cover blocks below reinforcement.
• Ensure proper spacing using spacers and chairs.
• Use standard bar bending machine for accurate bends.
• Avoid excessive re-bending of reinforcement bars.
• Ensure proper lap lengths wherever required.
• Check reinforcement alignment before concreting.
• Use Fe500/Fe500D steel unless specified otherwise.
• All dimensions should be measured along centerline of reinforcement.

Common Mistakes in Footing BBS

• Ignoring clear cover deduction.
• Ignoring bend deduction.
• Using overall dimensions directly.
• Wrong spacing interpretation.
• Incorrect rounding of bar numbers.
• Wrong unit conversion between mm and m.
• Improper anchorage calculations.
• Incorrect cutting length calculations.

Important IS Code References

• IS 456 : 2000 → Plain and Reinforced Concrete
• IS 2502 : 1963 → Bending and Fixing of Reinforcement Bars
• SP 34 → Handbook on Reinforcement Detailing
• IS 1786 → High Strength Reinforcement Steel
• IS 13920 → Ductile Detailing

Developed By

Mohan Dangi (Gold Medalist)