Different types of stirrups are used in reinforcement according to the loads and stress induced on the structural members.

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## Why are the Stirrups & Ties provided in reinforcement?

• It holds the rebars in position and prevents deformation.
• It positions the rods in the same alignment.
• To secure the beam and column from the buckling and shear failure.
• The stirrups are resisting the rods under compression or tensile force.

## Cutting Length of Stirrups Formula

The only formula that we need to remember is,

Cutting Length of Stirrups = Perimeter of stirrup + Hook Length â€“ Elongated Bend Length

Why subtracting the bend? â€“ Because when we bend the steel bar, the barâ€™s length will slightly increase due to the stretch (elongation). The length depends on the angle of the elongation. Thatâ€™s the reason we subtract it.

## Cutting Length of Rectangular StirrupsÂ

Letâ€™s calculate the cutting length of the above rectangular stirrupÂ

Cutting Length of Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 3 x 90Â° bends â€“ 2 x 135Â° bends

= 2 (520+220) + (2 x 9d) â€“ (3 x 2d) â€“ (2x3d)

= 2(1480) + (2x9x8) â€“ (3x2x8) â€“ (2x3x8) = 3008 mm

## Cutting Length of Square StirrupsÂ

Letâ€™s calculate the cutting length of the above square stirrupÂ

Cutting Length of Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 3 x 90Â° bends â€“ 2 x 135Â° bends

=Â  4a + (2 x 9d) â€“ (3 x 2d) â€“ (2x3d)

= (4Ã—200) + (2x9x8) â€“ (3x2x8) â€“ (2x3x8) = 848 mm

## Cutting Length of Circular StirrupsÂ

Letâ€™s calculate the cutting length of the above circular stirrupÂ

Cutting Length of Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 2 x 135Â° bends

=Â  2Ï€r + (2 x 9d) -(2x3d)

= (2Ã—3.14Ã—300) + (2x9x8) â€“ (2x3x8) = 1980 mm

## Cutting Length of Triangular Stirrups

Letâ€™s calculate the cutting length of the above triangular stirrupÂ

Cutting Length of Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 4 x 135Â° bends

To find out the perimeter of the triangle stirrup, we need to calculate the Value of H

As from the diagram (pythagorean theorem), H = âˆš(a2)+((b/2)2)

H = âˆš(3502)+(1252) = 372 mm

Cutting Length of Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 4 x 135Â° bends

(Perimeter of stirrup = a + H + H = 250+372+372 = 994 mm

=Â  994 + (2 x 9d) â€“ (4x3d) = (994) + (2x9x8) â€“ (4x3x8) = 1042 mm

## Cutting Length of Diamond Stirrups

Cutting Length of Diamond Stirrup = Perimeter of Stirrup + 2 x Hook Length â€“ 3 x 90Â° bends â€“ 2 x 135Â° bends

= (4 x y) + (2 x 9d) â€“ (3x2d) â€“ (2x3d) = (4*y) + 18d-6d-6d = 4y + 6d

In order to get perimeter of the diamond stirrup, we have find out the value of y (ref the diagram)

a = 400 â€“ (2Ã—25) = 350 mm

b = 450 â€“ (2Ã—25) = 400 mm

(pythagorean theorem), y2 = (a/2)2 + (b/2)2 = (350/2)2 + (400/2)2

Y = 266 mm

Therefore, cutting length of Diamond Stirrup = (4Ã—266) + (6 x8) = 1112 mm

Happy Learning ðŸ™‚

Satheesh is a Civil Engineer who has more than 11+ Years of experience in residential construction. He is the author, editor of Civil Planets