Civil Engineering (CE) Exam > Civil Engineering (CE) Questions > If a descending gradient of 1 in 25 meets an ...
Start Learning for Free
If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will be
- a)130 m
- b)30 m
- c)310 m
- d)630m
Correct answer is option 'A'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
If a descending gradient of 1 in 25 meets an ascending gradient of 1 i...
Most Upvoted Answer
If a descending gradient of 1 in 25 meets an ascending gradient of 1 i...
Given:
Descending gradient = 1 in 25
Ascending gradient = 1 in 40
Headlight sight distance = 100 m
To find: Length of valley curve required
Formula used:
L = 3.6aV²/2gd
where
L = Length of valley curve
a = Rate of change of centrifugal acceleration (m/s³)
V = Design speed (m/s)
g = Acceleration due to gravity (m/s²)
d = Rate of change of gradient (%)
Calculation:
1. Rate of change of centrifugal acceleration (a):
a = V²/r
where
V = Design speed (m/s)
r = Radius of curve (m)
To find the radius of curve, we need to find the degree of curvature (D):
D = 2arctan(1000G)
where
G = Rate of change of grade (% per 30 m)
G = -1/25 - 1/40 = -0.068
D = 2arctan(1000(-0.068)/30) = -8.23°
The radius of curve (r) can be found using the formula:
r = 5729.58/D (in meters)
r = 5729.58/-8.23 = -695.4 m (negative sign indicates a left-hand curve)
As radius cannot be negative, we take the absolute value:
r = 695.4 m
Now, we can find the rate of change of centrifugal acceleration:
a = V²/r
2. Design speed (V):
Design speed is usually taken as 80 km/h (22.22 m/s) for two-lane highways.
3. Acceleration due to gravity (g):
g = 9.81 m/s²
4. Rate of change of gradient (d):
d = G/100 = -0.068/100 = -0.00068
5. Length of valley curve (L):
L = 3.6aV²/2gd
L = 3.6(22.22)²/(2*9.81*-0.00068)
L = 130.7 m
Therefore, the length of valley curve required for a headlight sight distance of 100 m is 130 m (approx). Hence, option (a) is the correct answer.
Descending gradient = 1 in 25
Ascending gradient = 1 in 40
Headlight sight distance = 100 m
To find: Length of valley curve required
Formula used:
L = 3.6aV²/2gd
where
L = Length of valley curve
a = Rate of change of centrifugal acceleration (m/s³)
V = Design speed (m/s)
g = Acceleration due to gravity (m/s²)
d = Rate of change of gradient (%)
Calculation:
1. Rate of change of centrifugal acceleration (a):
a = V²/r
where
V = Design speed (m/s)
r = Radius of curve (m)
To find the radius of curve, we need to find the degree of curvature (D):
D = 2arctan(1000G)
where
G = Rate of change of grade (% per 30 m)
G = -1/25 - 1/40 = -0.068
D = 2arctan(1000(-0.068)/30) = -8.23°
The radius of curve (r) can be found using the formula:
r = 5729.58/D (in meters)
r = 5729.58/-8.23 = -695.4 m (negative sign indicates a left-hand curve)
As radius cannot be negative, we take the absolute value:
r = 695.4 m
Now, we can find the rate of change of centrifugal acceleration:
a = V²/r
2. Design speed (V):
Design speed is usually taken as 80 km/h (22.22 m/s) for two-lane highways.
3. Acceleration due to gravity (g):
g = 9.81 m/s²
4. Rate of change of gradient (d):
d = G/100 = -0.068/100 = -0.00068
5. Length of valley curve (L):
L = 3.6aV²/2gd
L = 3.6(22.22)²/(2*9.81*-0.00068)
L = 130.7 m
Therefore, the length of valley curve required for a headlight sight distance of 100 m is 130 m (approx). Hence, option (a) is the correct answer.
Free Test
FREE
| Start Free Test |
Community Answer
If a descending gradient of 1 in 25 meets an ascending gradient of 1 i...
Given SSD = 100 m
From headlight sight distance,
From headlight sight distance,
Attention Civil Engineering (CE) Students!
To make sure you are not studying endlessly, EduRev has designed Civil Engineering (CE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Civil Engineering (CE).
|
Explore Courses for Civil Engineering (CE) exam
|
|
Similar Civil Engineering (CE) Doubts
Top Courses for Civil Engineering (CE)View all
If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer?
Question Description
If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? for Civil Engineering (CE) 2024 is part of Civil Engineering (CE) preparation. The Question and answers have been prepared according to the Civil Engineering (CE) exam syllabus. Information about If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Civil Engineering (CE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer?.
If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? for Civil Engineering (CE) 2024 is part of Civil Engineering (CE) preparation. The Question and answers have been prepared according to the Civil Engineering (CE) exam syllabus. Information about If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Civil Engineering (CE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer?.
Solutions for If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for Civil Engineering (CE).
Download more important topics, notes, lectures and mock test series for Civil Engineering (CE) Exam by signing up for free.
Here you can find the meaning of If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer?, a detailed solution for If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? has been provided alongside types of If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice If a descending gradient of 1 in 25 meets an ascending gradient of 1 in 40, then the length ofvalley curve required for a headlight sight distance of 100 m will bea)130 mb)30 mc)310 md)630mCorrect answer is option 'A'. Can you explain this answer? tests, examples and also practice Civil Engineering (CE) tests.
|
|
Explore Courses for Civil Engineering (CE) exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup