Reinforcement in one way slab

Stepwise Procedure to Calculate Reinforcement in one way slab

Reinforcement in one way slab

Reinforcement is nothing but the steel rod. So, here we will discuss the quantity and weight of Reinforcement i.e steel rood in the one-way slab.

Q) Calculate the quantity and weight of steel rod in a one-way slab having length 6 m, width 2.5 m. The diameter of the main bar is 12 mm in diameter with 100 mm c/c spacing and the diameter of the distribution bar is 8 mm with 130mm c/c spacing. The clear cover is 30 mm ( top to bottom ) and the thickness of the slab is 150 mm.

Reinforcement in one way slab
Slab Reinforcement

Solution,

 Given that;

      Length = 6 m

     Width = 2.5 m

     Main bar = 12 mm @ 100 mm c/c

     Distribution bar = 8 mm @ 130 mm c/c

     Clear cover = 30 mm From top to bottom

      Thickness = 150 mm

Step -1 : Calculation of no. of bars

      Calculate the number of bar required in both main and distribution bar.

  Formula = ( Total length – clear cover)/c/c spacing +1

      No. of main bar = ( 6000-(30+30))/100 +1

                                    = 5940/100 +1

                                   = 60.4    61 bars

No. of distribution bar = (2500 – (30+30)/130 +1

                                         = 2440/100 +1

                                         = 25.4    26 bars

Step -2 : Cutting length

        For main bar:

            Formula: L+(2* Ld) +(1*0.42D)- (2*1d)

Where,

   L = Clear span of the slab

   Ld = Development length which is equal to 40d ( d is diameter of bar)

0.42D = Inclined length

1d = 450 bends

 First we should calculate the length of ‘D’.

 D = Thickness – 2* clear cover at top,bottom – dia of bar

     = 150- 2*30 -12

  D = 78 mm

Putting the values in above equation

Cutting length = 2500 + (2*40*12) +(1*0.42*78) – (2*1*12)

Cutting length = 2500+960 +32.76 – 24

                            = 3468.76 mm     3469 mm (or3.469 m)

For distribution bar:

 = clear span + (2* development length)

6000 + ( 2*40*8)

 = 6640 mm ( or 6.64 m)

Conclusion:

Main bar:

 Number of bar = 61

Length  = 61 * 3.469 m = 211.609 m

Distribution bar:

Number of bar = 26

Length = 26 * 6.64 m = 172.64 m

I hope you understood the procedure to calculate reinforcement in one way slab.

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