Civil Engineering - Highway Engineering - Discussion

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

[A]. 1 in 40
[B]. 1 in 50
[C]. 1 in 60
[D]. 1 in 70
[E]. none of these.

Answer: Option A

Explanation:

No answer description available for this question.

Yugananth P said: (Aug 26, 2013)  
e = V^2/225R.

= 75 * 75/(225*1000).

= 1/40 (or).

= 1 in 40.

Arnab Chanda said: (Mar 23, 2014)  
But it is not declared that 1000 m is the radius of the curve.

Muleta Totoba said: (Mar 24, 2014)  
Right it is not declared but the term curve seems something to be the given figure 1000 is the radius.

Surya said: (Aug 2, 2014)  
e = V^2/gR.
V = 75% of design speed.
V = 0.75*75.
v = V/3.2.

Jay Mishra said: (Aug 28, 2014)  
I think superelevation = v^2/127r.

Deepak Mittal said: (Sep 17, 2014)  
No it should not be v^2/127r. If the value of f then you can take the v^2/127r. Otherwise V^2/225R.

Biswa said: (Nov 17, 2014)  
e = (0.75v)^2/Rg.

v in m/s.

Ans: 1 in 40.

Reshma said: (Dec 3, 2014)  
We have to design for 75% speed means super elevation for mixed traffic.

So,
e = (0.75V)^2/gR = V^2/225R.

Anitha said: (Dec 26, 2014)  
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.

Shankar Meghwar said: (Jan 24, 2015)  
R = V^2/225(e+fs).

Consider coefficient of friction as fs = 0.

Therefore R = V^2/225 e.
OR
e = V^2/225 R.
= 75*75/(225*1000).
= 0.025.
OR
= 1 in 40.

Manoj Kumawat said: (Feb 24, 2015)  
According IRC : The super-elevation is calculated for 75% of design speed.

So e = V^2/225R.

27-27 said: (Mar 14, 2015)  
Design speed is given use: e = (0.75v)^2/gR.

In a question if they are given only speed then use: e = v^2/gR.

Aditya said: (Jun 26, 2015)  
Guys can you please tell me the density of GSB, WMM, DBM and also BC?

Banoth Ramesh said: (Aug 3, 2015)  
ANS (A).

e = V^2/225R.
e = 0.025 = 1 in 40.

Ram Kumar said: (Oct 10, 2015)  
e = v^2/(127R) this formulas use.

And get the super elevation.

Pratik said: (Oct 13, 2015)  
Radius is not mentioned.

Mohamed Yaagob said: (Jan 30, 2016)  
F = 0 V = 0.75 V design speed.

E = (0.75 V)^2/(127 R).

Prashant said: (Feb 24, 2016)  
1000 m is length of curve here, not radius.

Ies Akp said: (Apr 1, 2016)  
1000 m is radius, it can't be length because there is no relation to provide length.

Osi said: (Jun 21, 2016)  
But we have studied it in the formula = v^2/126R. I am confusing which one is correct.

Miki said: (Jul 30, 2016)  
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.

Ravindra said: (Aug 21, 2016)  
The given answer is true, don't confuse it.

Jatav Shurjeet Singh said: (Sep 2, 2016)  
It is the right answer, it will use v^2/225r.

Jack said: (Sep 8, 2016)  
A District road having the mixed traffic condition so speed is reduced by 25%.

Super elevation e = V^2 / 225 R.
e = 75 * 75/225 * 1000
= 0.025.

so for 1m,
1/0.025 = 40.
=> 1 in 40.

Shailendra Kumar said: (Oct 9, 2016)  
I think the formula of superelevation e= v^2/225R.

So we put all values as given in the question e = 75 * 75/225 * 1000.
e = 1/40.

Kruti Nayak said: (Oct 17, 2016)  
v^2/225R is correct.
v^2/127R when f = 0.

Joel said: (Oct 17, 2016)  
The provided answer 1 in 40 is correct.

Happy said: (Dec 1, 2016)  
But, here v^2/225 is the highest unit of super-elevation.

Mukeah Senani said: (Dec 13, 2016)  
E = V^2/225R -> this method is Right.

Jayrajsinh said: (Dec 14, 2016)  
Practically super elevation e = v^2/225R.

So answer 1 in 40 is correct.

Sonu said: (Dec 19, 2016)  
If f is not given so we apply e = v^2/225R . The answer is 1 in 40.

Titan said: (Dec 21, 2016)  
Why is everyone assuming R=1000?

I think the curve length is 1000, not R. And the angle is not given.

Yohannis said: (Jan 12, 2017)  
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.

Danjah said: (Jan 14, 2017)  
here 1000 m is the length of curve, not radius.

Haylee Ethio said: (Feb 19, 2017)  
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.

Rehi said: (Feb 24, 2017)  
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: (Apr 2, 2017)  
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.

Naren said: (Apr 3, 2017)  
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: (Apr 4, 2017)  
V^2/127R is the formula for super elevation.

We will use use this (V^2/225R )formula only mixed traffic condition is given.

Palash Mondal said: (Apr 8, 2017)  
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.

Babugouda said: (May 5, 2017)  
Here,

e = v2/gr when v is in m/s.
e = v2 /127r when v is in kmph.

Sameer Naik said: (Jun 28, 2017)  
Why used 75% in que not mention mixed traffic?

Rajesh Kumar Saini said: (Aug 19, 2017)  
1/40 is the right answer.

Harveer Singh said: (Aug 26, 2017)  
1 in 40 is the right answer.

V^2/125r ( f is not given).

Yamir said: (Aug 28, 2017)  
F is not gives that doesn't mean we will not use 127 Maximum times we use 127 for already designed roads.

Azanaw said: (Sep 13, 2017)  
Why 75% is taken for design speed?

Janardhan said: (Sep 16, 2017)  
e=V2/225R when V in KMPH,
e=v2/127R-f ,if f is given,
and v in m/s,other wise e=v2/127R if f is not given.

Himanshu Kumar said: (Sep 29, 2017)  
But there speed in kilometer and horigental curve in meter so how it is possible? Please explain.

Deven Negi said: (Oct 26, 2017)  
Radius are not mentioned.

Manish Chandel said: (Jan 4, 2018)  
e=v^2/225*R is correct.

Dj.Thakur said: (Jan 15, 2018)  
For design of superelevation on road:-

(1)- design superelevation for 75% of design speed. (Hence s.e. resists 75% of centrifugal force rest is balanced by road friction)

Haroon said: (Mar 4, 2018)  
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.

Anmol said: (Jul 2, 2018)  
It's we have already given the design speed so we will use v2/127r.

Dev said: (Aug 15, 2018)  
Here it's v^2/127r.

Anwar Zaib said: (Sep 1, 2018)  
To determine super elevation we need only f- value, design speed and radius of the curve. So, if it is not mentioned then directly take the value with the unit of distance i.e meter.
the formula for mix traffic.

e + f = V^2/225R
HERE
f = 0 R=1000m and V =75kmph
so
e= 0.025 (1/40).

Surafel Belayneh said: (Sep 13, 2018)  
A District road having the mixed traffic condition so speed is reduced by 25%.

Super elevation e = V^2/225 R.
e = 75 * 75/225 * 1000.
= 0.025.

So for 1m,
1/0.025 = 40.
=> 1 in 40.

Yash said: (Nov 19, 2018)  
Already design speed is given, then why it converted again to design speed? Please tell me.

Sonam Phuntsho said: (Jan 6, 2019)  
What is the location of the road is on hilly area?

Mayur said: (Jan 24, 2019)  
Use e= (0.75v)^2/gr.

Singh Bushan Chib said: (Mar 6, 2019)  
It is right 1/40 by using the formula.

Rahul said: (Apr 19, 2019)  
In this question clearly mentioned design for the road not for any particular vehicle.

In the design of road assume friction is zero and 75% velocity ie formula of e is v^2/225R.

Tabaamith said: (May 12, 2019)  
Convert 75km/hr to m/ sec, which comes 20.85m/sec.
Take velocity as 75% of design speed.
Now, e= (0.75 * 20.85)^2/ 9.81X1000 = 0.024.
In ratio 1/1/0.024 = 1 in 40.

Kara Lala said: (May 20, 2019)  
GSB - Granular Sab Base.

WMM - Wet Mix Macadam.

Arjun said: (Sep 16, 2019)  
Design superelevation is always taken as 75% of the Design Speed hence it is e = v^2/225R.

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