Civil Engineering - Highway Engineering - Discussion
Discussion Forum : Highway Engineering - Section 1 (Q.No. 1)
1.
A district road with a bituminous pavement has a horizontal curve of 1000 m for a design speed of 75 km ph. The super-elevation is
Discussion:
95 comments Page 4 of 10.
Sonu said:
9 years ago
If f is not given so we apply e = v^2/225R . The answer is 1 in 40.
Titan said:
9 years ago
Why is everyone assuming R=1000?
I think the curve length is 1000, not R. And the angle is not given.
I think the curve length is 1000, not R. And the angle is not given.
Yohannis said:
9 years ago
The question stated that 75km/hr is design speed, thus simply we can calculate e=(75^2)/225R. b/c 'f' is not given.
There fore, 1:40 is the correct answer.
If 'f' were given, we use (e+f) = (75^2)/127R.
There fore, 1:40 is the correct answer.
If 'f' were given, we use (e+f) = (75^2)/127R.
Danjah said:
9 years ago
here 1000 m is the length of curve, not radius.
Haylee Ethio said:
9 years ago
Well,
We Have,
R=1000m
V= 75Km/h
Required?
Superelevation(e)
e=v^2/225R
= 75^2/225(1000)
=1/40 is the Correct one.
We Have,
R=1000m
V= 75Km/h
Required?
Superelevation(e)
e=v^2/225R
= 75^2/225(1000)
=1/40 is the Correct one.
Rehi said:
9 years ago
Actually, in the problem, it shows that horizontal curve is 1000m but in explanation, they take 1000m as a radius why don't they take it as length of the curve?
Sharad said:
9 years ago
Let's clear something out first,
e+f=v^2/127r (When V is in kmph) and
e+f=v^2/225r (When V is in mph)
For initial design, we assume mix traffic and hence the velocity reduces to 75% and f is taken as 0.
So, the equation will be e=(0.75v)^2/127r.
Now, the answer will be 0.0249 or 1 in 40.
e+f=v^2/127r (When V is in kmph) and
e+f=v^2/225r (When V is in mph)
For initial design, we assume mix traffic and hence the velocity reduces to 75% and f is taken as 0.
So, the equation will be e=(0.75v)^2/127r.
Now, the answer will be 0.0249 or 1 in 40.
Naren said:
9 years ago
Why we take 1000 as R why don't we take it as the length of the curve? Could anybody please explain me this?
Geetha said:
8 years ago
V^2/127R is the formula for super elevation.
We will use use this (V^2/225R )formula only mixed traffic condition is given.
We will use use this (V^2/225R )formula only mixed traffic condition is given.
Palash mondal said:
8 years ago
The actual formula of super elevation is;
We know the super elevation is calculated for 75% of design speed.
So,
E = (.75V)^2/GR.
V = Desing speed.
G = Gravity.
R = Radios.
Now,
E = (.75 * 20.83)^2/9.81 * 1000,
V = 75 * 1000/60 *60,
V = 20.83m,
E = .2488,
E = .25 approx,
E = 1/40 answer.
We know the super elevation is calculated for 75% of design speed.
So,
E = (.75V)^2/GR.
V = Desing speed.
G = Gravity.
R = Radios.
Now,
E = (.75 * 20.83)^2/9.81 * 1000,
V = 75 * 1000/60 *60,
V = 20.83m,
E = .2488,
E = .25 approx,
E = 1/40 answer.
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