 How to calculate the quantity of concrete in the retaining wall on site

What are Retaining Walls?

Retaining walls are the Rigid walls constructed to retain the material such as soil, water, etc. the retaining wall is constructed in such a way that one side of the wall is straight and the other side of the wall which is facing to the material such as soil, water, etc. is in tapered shaped. So that it can retain the soil, water, etc. see figure,

in this article, you will know how to calculate the quantity of concrete in the retaining wall at the site when the whole wall is constructed in parts

In this article, we will discuss how to calculate the quantity of concrete in the retaining wall.

Calculation of Volume of Concrete in Retaining Wall

As we can see that the height of the retaining wall is 5 MTR or 5000 MM.  The Retaining Wall is constructed on the foundation known as the Raft Foundation. The length of the foundation is 10mtr. The width and depth of the foundation are 8mtr and 800mm respectively. As shown in Figure.

Now we have to calculate the volume of concrete in Retaining Wall and Raft Foundation.

For Retaining Wall

To Calculate the volume of concrete in Retaining Wall we have to find out the following things from drawings

Length = 10m

Width = 900mm from Bottom

= 300mm from top

Height = 5m

Volume = length x Average Width x Height

= 10 x ((0.9+0.3)/2) x 5

=30 Cum

For Raft Foundation

Length = 10m

Width = 8m

Height = 0.8m

Therefore volume = length x Width x height

= 10 x 8 x 0.8

= 64cum

So the volume of retaining Wall is 30 Cum and Raft Foundation is 64 Cum

Total Volume of Concrete is 94 Cum

Now, As per Site If we find the volume of concrete in Retaining Walls, we have to construct this retaining wall of height 5 m in parts. As the shuttering work is not done throughout the wall, it is done in parts.

For example, we have a shuttering plate of size 1200mm and these plates are attached with channel ISMC of 100mm from top and bottom. Therefore first lift is made of height 1400mm( one shuttering plate 1200mm and two channels  of 100mm each.)

Now we have to Find out the volume of concrete in First lift of retaining Wall of height 1400mm

Therefore, we have to calculate the top width of the first lift i.e. we have to calculate the value of X

To find the value of BC we will use a similar triangle property.

In triangle ABC and triangle ADE

3600/5000 = BC/600

BC = (3600 x 600)/5000

BC = 432( you can also find this dimension in AutoCAD very easily)

Therefore X = 432+300

= 732mm

Now we will be able to find the volume of concrete in 1st lift.

Length = 10m

Width = 0.732m top width

= 0.9m bottom width

Height = 1.4m

Therefore volume of concrete of retaining wall 1st Lift = 10 x ((0.732+0.9)/2) x 1.4

= 11.424 cum

Similarly, we will find out the top width of the remaining lifts as shown in the figure.

Volume of concrete in 2nd lift of retaining wall

Length = 10m

Width = 0.576m top width

= 0.732m bottom width

Height = 1.3m

Volume = 10 x ((0.576+0.732)/2) x 1.3

= 8.502cum

Volume of concrete in 3rd  lift of retaining wall

Length = 10m

Width = 0.420m top width

= 0.576m bottom width

Height = 1.3m

Volume = 10 x ((0.420+0.576)/2) x 1.3

= 6.474cum

Volume of concrete in 4th   lift of retaining wall

Length = 10m

Width = 0.300m top width

= 0.420m bottom width

Height = 1.3m

Volume = 10 x ((0.300+0.420)/2) x 1

= 3.6cum

Therefore total volume of concrete in retaining walls is  30 cum.

With this, you can calculate the volume of concrete of retaining wall as per site and as per drawing.

Thank you

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