# STEEL CALCULATION FOR BEAM (BBS)

# Steel Calculation for beam:

The quantity of the beam is very easy and simple. Just you need to know about the basics of Beam. Let solve this example to understand better.

### Example:

Let us we have a simply supported beam having a cross section **300×500 mm** and length of the beam is **4 m**. The main bars used in this beam is **20 mm** and the support bar diameter is **16 mm**. The diameter of the stirrup is **12 mm** and the spacing of stirrup is at an end is **100 mm** and **150 mm** at the mid support of the beams.

- Calculate the required quantity of steel for the beam?
- Cutting length of stirrups?
- Calculate the weight of steel?

#### Given data:

Length = 4 m

Height = 500 mm

Width = 300 mm

#### Solution:

Main bars (20 mm):

length = length of beam + development length – bend

#Where

<bend 45deg=1d 90deg=2d 135deg=3d >

<development length is the grip between steel and concrete >

**Length:**

Main = 4000 + (50d×2) – (2d×2)

= 4000 + (50×20×2) – (2×20×2)

= 4000 + 2000 – 80

=**5920 mm or 5.92 m Ans..**

For 2 nos

= 5.92×2

=11.84 m

**Weight**

= d^{2}/162 × length

=20 × 20/162 × 11.84

=**29.2 kg**

Supports bars (16 mm):

Length = length of beam + Ld – bend

#where

<for 90 deg bend=2d>

Support = 4000 + (50d×2) – (2d×2)

= 4000 + (50×16×2) – (2×16×2)

= 4000 +1600 – 64

=**5536 or 5.536 m Ans…**

For 2 nos

= 5.536 × 2

=11.072 m

**Weight**= d^{2}/162 × length= 16 × 16/162 × 11.072= **16.47 kg**

#### Stirrups:

Length is divided into 2 way 1st is at support and 2^{nd} is at mid support.

For end supports: (spacing 100 mm)

Length / 3:

= 4000/3

= **1333.3 m**

No of stirrups

= Length/spacing + 1

= 1333.3/100+1

=**14.33 use 15 No’s**

Total no of stirrups for end supports

= 15×2

= **30 No’s**

For mid supports: (spacing 150 mm)

Length = 1333.3 m

No of stirrups

= length /spacing + 1

= 133.3/150+1

= 7.88 use **8 nos **

**Cutting length of stirrups:**

Cross section of stirrups is

Width = 300 mm

Height = 500 mm

A is horizontal length of stirrup

= 300 – (2 x clear cover) – (2 x half of bar dia )

= 300 – (2 x 30) – (2 x 6)

= **228 mm**

B is vertical length of stirrup

= 500 – (2 x clear cover) – (2 x half of bar dia )

= 500 – (2 x 30) – (2 x 6)

= **428 mm**

**Cutting**** length of one stirrups is**

Cutting length

= (2 x A)+(2 x B)+(2 x 10D)-(3d x 2)-(2d x 3)

#where

<10d is hook and 3d is bend 135 for deg and 2d is bend for 90 deg>

<In one stirrups 5 bend is required>

Cutting Length:

= (2 x 228)+(2 x 428)+(2 x 10 x 12)-(3 x 12 x 2)-(2 x 12 x 3)

= 456 + 856 + 240 – 72 – 72

= **1408 mm or 1.408 m**

For total 38 stirrups

= 1.408 x 38

= **53.50 m**

**Weight of stirrups is **

= d^{2}/162 x length

= 12^{2}/162 x 53.50

= **47.55 kg**

**Total weight of steel**

= Main bars + Supports bars + Stirrups

= 29.2 + 16.47 + 47.55

= **93.22 kg**

**Read also:- **http://www.civilclick.com/how-to-calculate-the-quantity-of-steel-in-two-way-slab-bbs/

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