Explanation: A
clothoid
is an ideal transition curve in which, length is inversely proportional to the radius of the curve. It is also known as Glover’s spiral. Explanation: Cubic parabola is also known as Froude’s transition curve.
What are the types of transition curve?
- Spiral or clothoid.
- Cubic parabola.
- Lemniscate.
What are the elements of transition curve?
- It’s radius must be infinite at origin on the tangent.
- Where the circular curve meet at that curve, on that point radius must be equal to circular curve’s radius.
- There must be not become any difference between rate of increase of superelevation and the rate of increase of curvature.
Which of the following objectives is a transition curve?
Objectives or Purpose
To
provide Super Elevation in a gradual manner and to reduce the radius from infinity at a straight junction to a radius R at curved junction gradually
. Transition curves also reduces the effect of sudden jerk on passengers due to the effect of centrifugal force induced on vehicles at curves.
Which shape normally is transition curve?
The Railway Board has decided that on Indian Railways, transition curves will normally be laid in the shape of
a cubic parabola
.
What are the functions of a transition curve?
Primary functions of a transition curves (or easement curves) are:
To accomplish gradual transition from the straight to circular curve
, so that curvature changes from zero to a finite value. To provide a medium for gradual introduction or change of required superelevation.
What are the requirements of a good transition curve?
- It should be perfectly tangential to the straight.
- The length of the transition curve should be such that curvature may increase at the same rate as the superelevation.
- This curve should join the circular are tangentially.
What is meant by a transition curve?
Transition curve is a curve in plan which is provided
to change the horizontal alignment from straight to circular curve gradually
means the radius of transition curve varies between infinity to R or R to infinity.
What is the ideal transition curve?
Explanation:
A clothoid
is an ideal transition curve in which, length is inversely proportional to the radius of the curve. It is also known as Glover’s spiral. Explanation: Cubic parabola is also known as Froude’s transition curve. It uses Cartesian co-ordinates which are required for setting the curve.
Why Lemniscate curve is used in road?
Minimum rate of change of curvature is required for both heavy and light vehicles
on the highway, and this necessitates the use of Lemniscate curves are used in highways, for which the radius relates to the sine function.
What is vertical curve?
Vertical curves are
used in highway and street vertical alignment to provide a gradual change between two adjacent grade lines
. … In figure below, vertical curve terminology is introduced: g1 is the slope (percent) of the lower station grade line. g2 is the slope of the higher station grade line.
What is a valley curve?
Valley curve or sag curve are
the vertical curves with convexity downwards
. These curves are provided either when a descending gradient meets an ascending gradient or a flat gradient or a descending gradient or when an ascending gradient meets another ascending gradient.
What is spiral curve?
Spiral curves are generally
used to provide a gradual change in curvature from a straight section of road to a curved section
. They assist the driver by providing a natural path to follow. Spiral curves also improve the appearance of circular curves by reducing the break in alignment perceived by drivers.
What is the advantage of transition curve?
The principal advantages of transition curves in horizontal alignment are the following: A
properly designed transition curve provides a natural, easy-to-follow path for drivers
, such that the centrifugal force increases or decreases gradually as a vehicle enters or leaves a circular curve. . . .
What is the shift in transition curve?
The
distance AB through which the main circular curve is shifted inwards to
accommodate the transition curve is called shift (s) or throw. The distance between the original centre O and the shifted centre O’ is usually small.
