Bar Bending Schedule For Slab, Estimation Of Steel Reinforcement In Slab

Bar Bending schedule plays a vital role in finding the quantities of reinforcement in structure. In order to find out the Bar bending schedule for slab or steel reinforcement in Slab, I recommend you to learn Basics of Bar Bending schedule and how to adopt concrete cover for different components of a building.

Bar Bending Schedule for Slab

There are 16 different types of slabs in construction. Well, the thickness of the slab generally varies between 4″ to 8″. We generally adopt 6″ (0.15m) slab thickness. For occasionally heavy loads we adopt 8″ and above thickness slabs.

Quantity of Reinforcement (Steel) required for Slab Or Bar Bending Schedule for Slab

In this post, I am finding out the Estimation of Steel reinforcement required for a Slab to work on this I considered a plan as shown below.
Primarily slabs are classified into two types One-way Slab and Two-way slab to know more about the differences refer here.

In one-way slab, Main bars are provided in a shorter direction (Cranked bars) and distribution bars are provided in Longer direction (Straight bars). Whereas in Two-way slab Main bars (cranked bars) are provided in both directions. Usually, the Two-way slab is adopted when the length and width of the slab are more than 4m.

Well to make you perfect in Bar Bending Schedule for a slab, I am considering a One-way slab and two-way slab as shown in the figure. Main bars and distribution bars are provided in the One-way slab. In two way slab,  distribution bars are provided on both sides of the slab.

Distribution bars:- These bars are straight bars.
Main bars:- These bars are cranked bars. Main bars are cranked at an angle of 45 Degree with the length of 0.42D

Where, D = Depth of Slab- Top cover – Bottom cover

Extra Bars:- The extra bar is provided at the bottom of Cranked bars to maintain the framework of the slab.
The length of the Extra bar is L/4.

Steps to calculate the Reinforcement required for Slab

1- Deduct the cover for finding the length of the bar.

2- Evaluate the length of the distribution bar

3- Calculate the Value of ‘D’ (Depth of the slab- Top cover- Bottom cover)

4- Find out the No. of Bars

5- Compute the Total wt of steel required for slab reinforcement.

Consider,

Dia of bars = 10mm , Spacing between bars = 0.10m , Depth of Slab = 0.15m

Floor Slab – 1 (Two-Way Slab)

Bars along X-Axis

Bars along Y-Axis

Total wt of Bars = 150.285+150.091 = 300.376Kgs 

For Floor slab -2 (One-way slab) 

As per the above figure Floor slab, -2 is a One-way slab. In this kind of slab Mains bars (cranked bars) are provided in shorter direction hence there is no need of calculating the crank bar length in Y-direction (from fig). Evaluate the length of Bar as given in the figure by deducting the covering length.  Whereas in X Direction Crank bar length is considered.