Construction Cost Estimating


Procedure to work out the volume of concrete for slabs, columns, beams, retaining wall & footing

This construction article sheds light on the following topics :-

How to work out the volume of concrete for Slabs, Beams, Columns, Footings & structural members of the building.

To work out the quantities of cement, sand, aggregate & water essential for any concrete volume; initially, it is required to compute the volume of concrete and then the quantities of separate components.

Definition of Volume:-

Select a box with length (1m), breadth,(1m) depth(1m) and fill it with concrete.
The Volume of concrete will be calculated as Length x Breadth x Depth= 1m x 1m x 1m =1m3
To fill 1m3 of box, 25KN of concrete is necessary. [1KN = 1000Kgs].
Density of Concrete = 25KN/m3
Volume is the computation of 3dimensional, which means the three dimensions are multiplied.
The basic definition of the volume = multiplication of the three dimensions = L x B x D

The formula is altered according to shape, but the procedure remains identical to work out the volume of any shape i.e., the three dimensions should be multiplied. As for instance, choose a cylinder that does not contain length and breadth. To work out the volume of a cylinder, the area of the circle is calculated and then it is multiplied by the height of the cylinder. (given below, mentioned circular column for cylinder example).

To get rid of confusion, apply the following formula for concrete volume calculation.

Formulae for Calculating Volume of Concrete:-

The Volume of concrete= Surface Area x Depth

Computation of Volume of concrete for Slabs:

A slab is in the shape of a rectangle, To measure the volume of necessary concrete for the slab, determine the surface area of the slab and then multiply it with the depth/thickness of slab.

Suppose, Length = 6m, Breadth = 5m and thickness/depth of the slab = 0.15m
Volume of Concrete = Area of rectangle x Depth
Area of Rectangle = Length x Breadth
The Volume of concrete = Length x Breadth x Depth = 6x5x0.15=4.5m3

Hence, 4.5m3of concrete is essential for constructing the above slab.
Keep in mind that all values should be calculated in m.
Computation of volume of concrete for the column:
The column is available in different shapes like rectangular or circular or hexagonal etc.
Volume of concrete = Surface Area x Depth
Rectangular column:
Suppose, Length = 0.6m, Breadth=0.4m, Height of column = 3m
Work out the top surface area and multiply it with the depth or height of the column.
Volume of Concrete = 0.6?0.4?3= 0.72m3

Circular column:

Suppose, radius of circle = 0.25m.
Volume of concrete for circular column = Surface Area of Circle x height of column.
Volume of Circular column = pr2 x 3 = 3.14 x 0.252 x3 = 0.58m3
How to work out the volume of concrete for beams :-
Beams normally come in rectangular shape. To work out the volume of necessary concrete for beams, work out the top or bottom surface area of beam and multiply with the depth of beams.
Volume of concrete for rectangular beam = Surface area x Depth = length x width x depth = 4?0.5?0.4=0.8m3

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Procedure to work out the volume of concrete for slabs, columns, beams, retaining wall & footing