# Calculation Formula Of Column, Beam And Slab

### Calculation Formula

The steel calculation formula is L x D2 /162

L = Length of bar

D = diameter of bar

### Steel Quantity of Column

Assuming the following data,

column size is 450 x 600 x 3000 mm

This type of staircase also available in roof systems supported with trusses. The purpose of stringer beams is to transform distributed loads to point loads.

It is known that the length of the bar is 3 m. By this we can calculate the weight of the bar and we have to calculate the weight of stirrups or ties. Dia of ties is 8 mm.

We have to calculate weight of 25 mm bar = 3 x (25)2/162 = 11.57 k.g

No. of bar = 8 so, weight of bar is = 11.57 x 8 = 92.56 k.g.

We have to calculate weight of 20 mm bar = 3 x (20)2/162 = 7.40 k.g

No. of bar is = 6 so,

Weight of bar = 7.40 x 6 = 44.4 k.g.

### Calculate Weight Ties or Stirrups

1. Hook Length is = 10d or 75 mm

2. 45° Bend = 1d

3. 90° Bend = 2d

4. 135° Bend = 3d

Cutting length of ties A = (column width – clear cover + column thickness – clear cover) + 2 no. of Hook – no. of 90 ° bend – 135 ° bend

Cutting length = (600 – 25 + 450 – 25) + 2(10d) – 3(2d) – 2(3d)

Cutting length = (575 +425) + 2(10 x 8) – 3(2 x 8) – 2(3 x 8)

Cutting length = 1064 mm

We can calculate all ties cutting length in this process.

### Steel Weight of Beam

Cutting length = Total length of the beam – 2 sides of clear cover + Both side Development length (Ld) + Lap length ( If the length of the beam is more than 12 m)

### Quantity of Beam Steel

Description |
No.of Beam |
Cutting Length in Meter |
No. Bar |
20 dia |
16 dia |
8 dia |

Top main bar | 1 | 20.95 | 4 | 83.8 | ||

Bottom main bar | 1 | 20.95 | 2 | 41.9 | 41.9 | |

Top Extra bar | 1 | 2.9 | 3 | 8.7 | ||

2.2 | 2 | 4.4 | ||||

2.75 | 2 | 5.5 | ||||

2.45 | 3 | 7.35 | ||||

Bottom extra | 1 | 4.945 | 2 | 9.89 | ||

3.52 | 2 | 7.04 | ||||

3.735 | 2 | 7.47 | ||||

Lap length (Top +Bottom) | 1 | 1.0 | 6 | 4.0 | ||

1 | 1.0 | 2 | 2.0 | |||

Ring (Grid 4-5) | 1 | 1.55 | 51 | 79.05 | ||

Ring (Grid 3-1) | 1.55 | 72 | 111.6 | |||

Total | 52.6 | 171.35 | 190.65 |

Total length of 20 mm bar = 56.6 m

Total length of 16 mm bar = 171.35 m

Total length of 8 mm bar = 190.65 m

Weight of 20 mm bar = 56.6 x 2.469 = 139.74 k.g. (1 m bar = 2.469 k.g)

Weight of 16 mm bar = 171.35 x 1.58 = 270.73 k.g. (1 m bar = 1.58 k.g)

Weight of 8 mm bar = 190.65 x 0.395 = 75.30 k.g. (1 m bar = 2.469 k.g)

### Calculation of Slab Steel

Spacing in slab bar c/c 150 mm

We have to use a main and cross 10 mm bar in the slab Before calculating.

Beam length from Grid-(L – M) is 7443 mm and Grid-(1 – 2) 5320 mm as given.

Width of the slab is 7443 that is the Width of two slabs for calculating S2 slab steel divide the width of 2 then we will get Width of S2 slab.

Width of slab S2 = 7443/2 = 3721.5 mm

Length of slab S2 = 5320 mm

we know that the main bar of slab laid in short span and crossbar laid in longer span.

First calculate the no. of bar = Length of span / spacing of bar + 1

Calculate the no. of bar of short span= 3721.5 / 150 +1 = 25.81 , approx = 26

Calculate the no. of bar of long span= 5320 / 150 +1 = 36.46 , approx = 36

Short span length = 3721.5 mm

Long span length = 5320 mm

Cutting length of short span = Length of span + Crank length – 45° bend

= 3721.5 + 0.42D – 2(1d)

D = Slab thickness – 2 side clear cover – dia of bar = 150 – 50 -10 = 90 mm

= 3721.5 + 0.42 x 90 – 2 x 1 x 10 = 3739 mm

No. of bar in short span = 26

Total cutting length = 26 x 3.739 = 97.21 m

Cutting length of Long span = 5320 + 0.42 x 90 – 2 x 1 x 10 = 5337.8 mm

No. of bar in long span = 36

Total cutting length = 36 x 5337.8 = 192.16 m

Weight of short span bar = 97.21 x 0.617 = 59.97 k.g. ( 0.617= 102/162 )

Weight of short span bar = 192.16 x 0.617 = 118.56 k.g.

We also can calculate the weight of the bender in the same process.

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