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
1 in 40
1 in 50
1 in 60
1 in 70
none of these.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
95 comments Page 3 of 10.

Haroon said:   8 years ago
e+f=v^2/gr, v in m/s.
e+f=v^2/127r, v in km/h.

For 75% of design speed f=0,as per irc.
e=(0.75v)^2/127r =v^2/225r.
e=75*75/(225*1000)=0.025=1:40.

AKINDELE ADEGBOLA said:   3 years ago
I need clarity on super elevation, how do they arrive at 225, 227 if e+f=v2/gr. I need steps by steps calculations.

Anyone, please explain to me.
(3)

Anitha said:   1 decade ago
We have to design for 75% speed.

So, e = (0.75v)^2/g.r;

v = 75kmph = 75/3.6 = 20.833.

e = (0.75*20.833)^2/(9.81*1000) = 0.02488.

1/40 = 0.025.

Kishor bist said:   2 years ago
Given data :

R = 1000 m.
V = 75 kmph = 75x(1000/3600) = 20.83m/s,
e = (0.75xv^2/gr).
= ((0.75x20.83)^2/(9.81x1000)),
= 0.025 = 1 in 40.
(6)

Chittaranjan sankhua said:   2 years ago
Given Option is wrong.

According to 1st, we have to convert the speed in m/s.
Then the e = v2/127r and e = v2/225r is for mix traffic.
(4)

Siva gubbala said:   3 years ago
Given data :

R = 1000 m
V = 75 kmph=75x(1000/3600)=20.83m/s
e = (0.75xv'2/gr)
= ((0.75x20.83)'2/(9.81x1000))
= 0.025 = 1 in 40.
(11)

Miki said:   9 years ago
Both the formula is correct, the only difference is in e = v^2/127R, uses 75% of speed, and in e = V^2/225R, we are directly used.

Pramit Samanta said:   5 years ago
If mixed traffic or maximum value was mentioned then it has to be e + f = V2/225R. Otherwise for design purpose e + f = V2/127R.
(1)

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.

MILI said:   3 years ago
You are absolutely right @Anitha.

We cannot use the formula e=v^2/225 directly, as the question does not mention Hill road.


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