Circular Stirrup Cutting Length Calculator

This calculator determines the cutting length of circular stirrups considering hook length and bend deduction according to common reinforcement detailing practice.

Input Details

Diameter of Circular Stirrup (D) in mm Centerline diameter of circular stirrup.

Bar Diameter (d) in mm 6 mm 8 mm 10 mm 12 mm 16 mm Diameter of reinforcement bar.

Hook Type 9d Hook 10d Hook 12d Hook Hook length used as per detailing practice.

Calculation Result

Formula Used

Circumference = π × D

Total Hook Length = 2 × Hook Length

Hook Length = Hook Multiplier × d

Bend Deduction for two hooks ≈ 0.84d

Final Cutting Length:

L = πD + 2(Hook Length) − Bend Deduction

Important: According to common bar bending schedules and SP-34 practices:

• One 45° bend deduction ≈ 0.42d
• Two bends deduction ≈ 0.84d
• Hook lengths are generally 9d, 10d, or 12d.

Explanation of Values

• D: Diameter of circular stirrup measured along centerline.
• d: Diameter of reinforcement bar.
• πD: Circumference of circular stirrup.
• Hook Length: Extra anchorage length provided at stirrup ends.
• Bend Deduction: Reduction in effective bar length due to bending.

Reference Table

Bend Type	Deduction
One 45° Bend	0.42d
Two 45° Bends	0.84d
90° Hook	Generally 9d to 12d

Reference Codes

• IS 2502 : 1963 – Code of Practice for Bending and Fixing of Bars.
• SP 34 – Handbook on Concrete Reinforcement and Detailing.
• IS 456 : 2000 – Plain and Reinforced Concrete Code.