Civil Engineering - Surveying - Discussion

Discussion Forum : Surveying - Section 1 (Q.No. 42)
42.
The slope correction for a length of 30 m along a gradient of 1 in 20, is
3.75 cm
0.375 cm
37.5 cm
2.75 cm.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
58 comments Page 5 of 6.

Sanjukta said:   9 years ago
Thank you for the explanation friends.

Nawa Raj Budha said:   9 years ago
Good explanations friends. Thank you.

Baloch said:   9 years ago
Slope correction = h^2 / 2l.
h = 20/30 = 1.5.
l = length.
By submitting the value you will get the answer.

MD FAISAL said:   9 years ago
In ABC triangle,

AC = l = 30m.
Slope = 1 : 20.

1 in20 so in 30 = (1/20) * 30 = 1.5

Therefore BC = 1.5m.

And AB extends to BB'.
And meet to points A as arc & B as a straight line.
Here BB'= correction of line,
= AC - AB.

AB = (30^2 - 1.5^2)^1/2
= 29.962m.

BB' = 30 - 29.962
= 0.0375m or 3.75cm.

Hima Bindu said:   9 years ago
How h =1.5?

Swamy said:   9 years ago
Hi, friends all give the good explanations. Thank you.

Ali said:   9 years ago
We know for 30 m length, h = 1.5

And given gradient is 1 in 20 i.e 1/20

So, the equation of slope correction is,

= h^2 / 2l

= 1.5^2 / 2*30 m

= 2.25 / 60m

= 0.0375 m or 3.75 cm

Kanhu said:   1 decade ago
Slope correction for a sloping ground = h^2/2l.

Where h = height.

l = length of the ground.

Maheshkumar said:   1 decade ago
In 1 in 20 means, 20m = 1m.

So total 30m length = 1.5m.

In Gradient 1 in 20 Means.

Imagine Triangle, length-30m & Height-1.5m.

Use Pythagoras theorem.

X2 = 302+1.52.
X = 30.0375m.

Change length = 30.0375-30.

= 0.0375m.
= 3.75cm.

Engr Attaullah Khan Tareen said:   1 decade ago
For 20 m, h = 1 m. So for 30 m, h = 1.5 m.

So that = h^2/2l = (1.5) 2/2*30 = 0.0375 m.

1 m = 100 cm so 0.0375*100 = 3.75 cm.


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