What is footing?
Footings are the part of foundations they lie below the Ground level (Sub Structure). Footings are very first RCC members in Buildings
What is Isolated Footing?
Isolated Footing is defined as a footing which is provided below the column and all the load is distributed to the footing and then further distributed to soil. Isolated footing is also known as Trapezoidal footing.
Calculation of volume of Concrete of isolated footing:
For calculation of Volume of Concrete of Isolated Footing we have to first identify the dimensions of isolated footing
In an Architectural Drawings there are two types of views
- Top View or Plan
- Cross Section View or Elevation
The top view is provided for measuring the area i.e. Length and Breadth of a given footing.
The cross section view of any structure is provided for measuring the height/thickness of the structure and more important it is used for Reinforcement detailing of the structure.
Now to find out the volume of concrete in isolated footing
Calculation of volume of concrete is done in two parts i.e.
V1 = Represents the volume of base of isolated footing.
V2 = Represent the volume of trapezoidal portion.
Calculate the Volume of concrete in V1
Volume V1 = L x B x H1
Where, H1 =height of base portion as shown in figure (ii)
L = Length of footing.
B= Breadth of Footing
Volume V1 = 1200 x 1000 x 200
=240000000 mm3 or it is equal to 0.24 cu-m.
Now Calculate the Volume of concrete in V2
Volume V2= H/3 (A1+A2+√(A1 x A2))
Here A1 = Area of bottom of footing
A2 = Area of top of footing
Now find out the values of A1 & A2
A1= L x B
= 1200 x 1000
= 1200000 mm2 or it is equals to 1.2 m2
A2= L1 x B1
= 600 x 500
= 300000 mm2 or it is equal to 0.3 cum
Here H = H2 – H1
= 450 – 200
= 250 mm or it is equal to 0.25m
Put the values of A1 and A2 in the formula to calculate the volume of isolated footing V2 part in cum
V2= H/3 (A1+A2+(√(A1 x A2))
= 0.25/3((1.2+0.3) + √(1.2x 0.3))
= 0.0833(( 1.5) + (0.6))
= 0.1749 cum
Total Volume V = V1 + V2
V = 0.24 + 0.1749
V = 0.414 cum
Therefore total volume of concrete in an isolated footing is = 0.414 cum