Trapezoidal Footing Formula with Example
Trapezoidal Footing Concrete Formula
As you know this type of footing makes from 2 different shapes.
- Rectangular Cubes (A)
- Truncated Pyramid Cubes (B)
Please See the Image Below:
If you want to calculate whole shape volume, you have to calculate both shapes one by one.
Let us Assume the whole shape size and dimensions.
Column Size- 3m X 4m
Column to Top edge Spacing- 0.5m
Whole Footing Size -7m X 8m
The total height of footing is 6m
A Shape Height is 2m
B shape Height is 3m
Now, we have the whole structure data, Now time to put all data in Formula.
First, we calculate Shape A
as you can see shape A is a just rectangular shape
we know the whole size of the footing is 7m X8m and the A shape Height is 2 m.
Area of A shape
A1 = L x W
A1= 8 x 7 = 56 m2
The volume of A Shape
Volume = Area x height
Volume = 56 x 2 = 112 m3 ———-A
Now we are going to calculate the Truncated Pyramid Cubes’ shape
V = h/3 (A1+A2+√((A1 x A2) ) )
Where h is the height of the trapezoidal shape
A1 Area of the lower shape
A2 Area of upper shape
A1 = L x W A2 = L x W
A1 = 7 x 8 A2 = 5 x 4
A1 = 56 m2 A2 = 20 m2
V =3/3 (56+20+√((56 x 20) ) )
V =109.46 m3 ————B
Above we calculate the volume of A (112 m3)
Now we add A+B= 221.46 m3
Trapezoidal Footing Total Volume is 221.46 m3.
For a Better Experience, you can watch this video.