Circular stirrups, also called circular lateral ties, are essential components in reinforced concrete columns. They provide lateral support to the main reinforcement and help maintain column integrity under loads. Calculating the cutting length of these ties is crucial for precise fabrication and minimal material waste.
Key Dimensions You Need to Know
Before diving into the formula, ensure that the following measurements are available:
Diameter of the Circular Column (D): 450mm
Clear Cover: 40mm
Diameter of the Stirrups Bar (d): 8mm
These values are vital to determine the accurate radius and, eventually, the cutting length.
Step-by-Step Formula to Calculate Cutting Length
To calculate the cutting length of the circular stirrup, we apply the following formula:
Cutting Length = [2πr + (2 × hook length) – (2 × hook bend deduction)]
Where:
r is the radius from the centerline of the stirrup
Hook length is assumed to be 10d
Hook bend deduction is 2d
Let’s calculate it step by step.
Calculating the Effective Radius (r)
The radius is not half of the column diameter alone. We must subtract the clear cover and half the stirrup diameter.
r = [0.5 × D] – Clear Cover – [0.5 × d]
Substitute the values:
r = (0.5 × 450mm) – 40mm – (0.5 × 8mm)
r = 225mm – 40mm – 4mm = 181mm
So, the effective radius for the cutting length is 181mm.
Applying the Cutting Length Formula
Now that we have r = 181mm, plug the values into the formula:
Cutting Length = (2 × π × 181mm) + (2 × 10 × 8mm) – (2 × 2 × 8mm)
Breakdown:
2 × π × 181mm = 1137.4mm
2 × 10 × 8mm = 160mm (Hook Lengths)
2 × 2 × 8mm = 32mm (Hook Bends)
Now combine:
Cutting Length = 1137.4mm + 160mm – 32mm
Cutting Length = 1265.4mm
Final Answer:
The cutting length of the circular stirrup is 1265.4mm or 1.265m
Conclusion: Precision Saves Time and Cost
Correct measuring correctly ensures structural safety and reduces wastage. Always include hook lengths and subtract bend allowances to maintain accuracy. This simple formula works for any circular column. Just input the correct values and follow each step.
Stay precise. Build strong.
Click Here To See How To Calculate The Total Load Over The RCC Columns
