# Civil Engineering - Highway Engineering - Discussion

### Discussion :: 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

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

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.

 Mohammed said: (Nov 6, 2019) @Azanaw. You will find a clear explanation in IRC 38 codebook. However, I will try to briefly summarise it to you. Basically superelevation is provided to counteract the centrifugal force experienced by a vehicle when it's negotiating a curve. Now counteracting the full centrifugal force developed for a given design speed would require us to provide superelevation of more than 7%. But IRC restricts the maximum value of e= 7%. So in practice for mixed traffic, most vehicles travel at less than design speed (where we have both slow and fast-moving vehicles) so as a compromise since we can\'t provide the actual value we design superelevation to resist the full centrifugal force developed at 75% design speed. Eg: If the design speed of a National Highway is 80kmph. We design the superelevation to fully resist the centrifugal force developed due to 75% of 80kmph = 60 kmph. This method of giving superelevation will not be inconvenient to fast-moving vehicles but would be of aid to slow-moving vehicles.

 Ramkishor Sahu said: (Dec 16, 2019) Superelevation is always. e+f=v^2/127R. But for the design of the superelevation we take, e=V^2/225R. So, Here velocity 75 kmph and horizontal curve 1000 meter given. That means it is the radius of the horizontal curve. Note:- Horizontal curve always given in the form of the radius. Put these values to find the horizontal curve, e = 75^2 / (225*1000). e = 1/40. Thank you.

 Jeet said: (Feb 23, 2020) Super elevation = V^2 / 225 R. = 75x75 / 225x1000. = 0.025 = 1 in 40.

 Just said: (Mar 2, 2020) 75*75/(225*1000) = 75/(3*1000) = 25/1000 = 5/200 = 1/40.

 Pramit Samanta said: (May 4, 2020) 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.

 Sushil said: (Jun 27, 2020) Super elevation = V^2 / 225 R. = 75x75 / 225x1000. = 0.025 = 1 in 40.

 Umesh said: (Oct 5, 2020) as per IRC e=v^/225.R. Here, In question, it should be 1000m radius

 Elavarasy R said: (Apr 11, 2021) v^2/225R. = 75 x 75/227 x 1000. = 0.025. =1in40.

 Dr. Anuj said: (Apr 17, 2021) This will as per the design steps given by IRC for heterogeneous traffic. Step one is, you have to find the value of e (superelevation) neglecting friction for 75% of design speed. If the value so obtained is less than 0.07, the design is over and that value is taken as the designed value of superelevation.