Civil Engineering - Highway Engineering - Discussion

Option D is correct because the answer is 0.78,

Since it is for hill road and accordingly we have

E= (18n/R) +(0.1V/√R).

Option A correct in single-lane road only mechanical widening is considered.

Because of single lane road we only consider mechanical widening i.e, nl^2/2R.

Then we get the answer is 0.225m.

If the radius is in b/w 50 to 300 provide extra widening on both sides equally (half of 0.225).

But in question, they are mentioned the road is hilly. So only 1 side is possible to provide. So the answer is 0.225/2 option D.

This answer is wrong because if we are considering only psychological widening we will get the answer as 0.589( the equation is V/9.5√R.)

But mechanical widening is mandatory for any case. In question, it is mentioned that the road is single lane so that the psy. widening will be=0
The psychological widening will be provided due to psychological reasons( only when the opposite vehicle is coming.
In single-lane roads no opposite vehicles).

Here the We=Wm only.
Ie, nl^2/2R= 0.225m is the ansr. i.e, option (a).
If they mentioned considering both mechanical and psychological widening the answer would be 0.225 + 0.589 = 0.813.

Correct Answer is option-A.
Because For Single Lane Road Phycological Widening Is 0.
So, Mechanical Widening= nl^2/2R.

R<50 m Provide Extra widening on the inner side.
50m<R<300m Provide Extra widening both sides of Curve.

Here;
V/(9.58*√R).
V=50kmph,
R=80m,
than put value.
50/(9.5*√80)= .588m.

For single-lane road only mechanical extra widening is required as per IRC i, e V/9.5√R.

Wps=V/9.5*√R.
Wps=50/9.5*√80=0.589
So answer =B.

Thanks for explaining @Balli Singh.

@All.

If you didn't consider mechanical widening on hill, it means you give the vehicle to shortcut path about the jump from hill with a minimum radius and 50kmph speed.

So (W = Wmech+Wphy) is correct formula for all types of roads.