Civil - Highway Engineering - Geometric Design Of Highways
1. Define
sight distance?
Sight distance in the actual length of road over
which a driver sitting at a specified height in a vehicle can see objects
either moving (or) stationary on the road surface.
2. What are
classifications of sight distance depending upon the situation?
1. Stopping
sight distance
2. Sate
overtaking sight distance
3. Sight
distance at intersection
3. Define
S.S.D?
Stopping sight distance is the minimum distance
required with in which a vehicle moving at designed speed can be stopped
without colliding with a stationary object on the road surface.
4. What
is the height of driver eye above the road surface?
IRC
recommended height of driver eye is 1.22m.
5. Define
reaction time:-
It is the time in seconds which a driver can take
from the instant the objects visible to him to the instant the brakes are
effectively applied.
6. Define
perception period?
Perception period is the time taken by an average
driver to realize a danger a head before actually trying to apply the breaker.
7. Define
overtaking sight distance (OSD)
The distance visible to the driver of a vehicle
intending to overtake another slow moving vehicle, without causing any
inconvenience (or) possibility of accident to the traffic in the opposite
direction in called overtaking sight distance (or) safe passing sight distance.
8. Define
design speed?
Design speed can be defined as the speed which is
permissible for safe and comfortable driving on a given surface of the highway.
9. What are
the two effects of centrifugal force?
1. Tendency
to overturn the vehicle.
2. Tendency
to skid the vehicle laterally.
10.
Define super elevation?
The outer edge of the road in raised above the
inner edge called super elevation (or) cant (or) banking.
11. What is the relation between super elevation,
continuant of friction and centrifugal force
e+f=v^{2}/9.8R e = super elevation whose
value is taken an 40 (or) 1/15 f = Lateral frictional coefficient whose value
in R = Radian of curve in
metros. g
= 9.8
V = speed
of vehicle in m/sec.
13. Define horizontal curve?
It is a curve in plan to provide
change in the direction of the central time by the road surface.
14.
What are the factors attesting the design of
curve?
1.Design
speed of the vehicle
2.Allowable
friction
3.Maximum
allowable super elevation.
4.Permissible
centrifugal ration.
15.
Define vertical curve?
It is a curve in the longitudinal
section of a highway to provide a easy change of the gradient.
16.
What are curve used in a highway.
1.Circular
curve
2.Transition
curve
3.Parabolic
curve
17.
What is the value of radian of the simple
curve?
R= 1720m app
18.
Define compound curve?
A compound curve currish of a
serial of hoot (or) more simple curve that run in the same direction and joint
at common tangent point.
19. Define Reverse curve?
A reverse curve consist of two
simple curve opposite direction that point at the common tangent point. This
common point in called the point of reverse curve
20.
What are the types of transition curve?
1.True
spiral (or clothed.
2.cubic
spiral.
3.cubic
parabolic.
4. Lemniscate's.
21.
What are characteristics of Transition curve?
1. It should
meet the straight path tangentially
2. It should
meet the circular curve tangentially
22.
What is the equation of a spiral transition
curve?
Ls = m � Q
Where m = �2 RL = a constant
Q = tangent of deflection angle in radians
23.
How many methods to determine the length of
transition curve?
(1) By the rate of charge of radial acceleration
(2) By empirical formula
24 . Define gradient?
It is the
rate of rise (or) fall of road level along if length
25.
What are the factors governs the gradient?
(1)characteristics
- of the
traffic.
(2)Physical
factors of the site such a drainage, safety,
Bridge,
approach Road and railway Line intersection etc.
26. What
are different types of gradient?
(1).
Maximum gradient (2).
Puling gradient
(3).
Limiting gradient (4).
Exceptional gradient
27. What
are the driaclvantager of Exceptional gradient?
(1).
More fuel consumption (2). More
friction losses
(3).
Efficiency of engine reducer (4). Early
fatigue to animals.
28. What
are the hyper of vertical curve?
1.
Summit curve 2. Valley
curve
29. what
is the minimum Radian of vertical curve?
The
minimum ration of the curve is given by
L R = ---
Q
30. What
is the length of valley curve?
L= 0.38
(NV 3) �
L = Total Length of valley curve N = Deviation angle
v =
Design speed in triumph