Necessary Methods For Estimation of a Sewer Line

We all are aware of the necessity of the sewer line. It is basically an underground pipe that is not only used in a residential area but also in commercial buildings or any other sort of buildings to drain sewage.

Here in this tutorial, we will learn to estimate materials for 300ft. long sewer line. The pipe length will be 6ft and the sewer line consists of a slope of 1:200.

Now as we start estimating, the first thing is that we have to assume the ground as level. Along with that, we will be looking for the following objectives in this tutorial:

1. Excavation
2. Dry Bajri
3. How many number of pipes are involved?
4. How many joints are involved?
5. Refilling of the trench?

The solution of all of the above is explained below:

(1) Excavation
Excavation = Sectional area x length 
Excavation = 3 x 3.5 x 300 = 3150 cft.

(2) Dry Bajri
Dry bajri = Sectional area x length 
Dry bajri = 3 x 0.75 x 300 = 675 cft.

(3) Number of concrete pipes
Number of pipes = total length/length of one pipe = 300/6 = 50

(4) Number of joints = 50 – 1 = 49

5) Refilling of trench
From the above sections (1) and (2) , we get
Excavation = 3150 cft.
Dry bajri = 675 cft.
Now, Refilling of trench = excavation – (pipe + dry bajri deduction) = 2277 cft.

Watch the step by step estimation as shown in the video below:

Video Courtesy: SL Khan