RCC Footing Calculation

In this exclusive civil engineering tutorial video, you will learn how to measure the quantity of steel for RCC footing of a G+3 building through bar bending schedule in excel.

Format of excel will contain several heads like group, shape of bar, span of member, straight of length, additional length for L, numbers of footings, numbers of bars as well as total cutting length.

Under the diameter of each bar, weight of bar per meter is also worked out.

The following formula is used to compute weight of bar per meter.

D² / 162 (here, D stands for diameter.)

The weight of bar per meter for 6 mm bar = 0.22 kg per meter
The weight of bar per meter for 8 mm bar = 0.395 kg per meter
The weight of bar per meter for 10 mm bar = 0.617 kg per meter
The weight of bar per meter for 12 mm bar = 0.889 kg per meter
The weight of bar per meter for 16 mm bar = 1.58 kg per meter
The weight of bar per meter for 20 mm bar = 2.47 kg per meter
The weight of bar per meter for 25 mm bar = 3.86 kg per meter
The weight of bar per meter for 32 mm bar = 6.32 kg per meter
The weight of bar per meter for 40 mm bar = 9.88 kg per meter

Group is divided as Group 1, Group 2, Group 3, Group 4, Group 5 etc. In Group 1, there are total 15 footings. The bars are provided in both direction (x, y) in footing.

In group 1, the length of footing and width of footing is given as 1.3 meter and 1.2 meter.

Now, it is required to work out the straight length of the bar. To perform this, the cover should be deducted from both sides of footing. 50 mm or 0.5 meter cover is provided to both the sides of the footing.

Also Read: RCC Footing Details And Types

So, straight length = footing length – 2 x cover

Now, it is necessary to provide extra length that will be bent at the depth section of the footing to create the shape of L. It is normally chosen as 130 mm or 0.13 meter. So, 0.13 meter will be provided in the cell arranged for extra length.

In group 1, the number of bars are arranged as follow :-
9 bars of 10 mm diameter in x direction and 8 bars of 10 mm diameter in y direction.
In footing, 10 mm diameter bars are only used.

The formula for working out the total cutting length is given as follow :-
Total cutting length = [Straight Length + Extra Length] x Numbers of footings x Numbers of bars.
In this way, one can find out the total length of bars for all the footings in each group.
Finally, all the lengths will be added together to get the total length of bars for all the groups of footings.

To get more clear idea, go through the following video tutorial.

Video Source: Unite Constructions And Unite Coaching