The document discusses transition curves in highways. Transition curves are curves that gradually change the horizontal alignment from straight to circular. This is done to introduce centrifugal force, super elevation, extra widening, and aesthetics gradually for driver comfort and safety. There are three main types of transition curves: spiral, cubic parabola, and lemniscate. The length of the transition curve can be calculated based on the rate of change of centrifugal acceleration, rate of introduction of designed super elevation, or empirical formulas based on vehicle speed and radius of the circular curve. The maximum length from these three criteria is used as the final length of the transition curve.

1. ‘’ TRANSITION CURVE
‘’
GOVERNMENT ENGINEERING COLLEGE, BHARUCH
5TH SEM CIVIL
HIGHWAY ENGINEERING(2150601)
Presentation Done By :
MITHAIALA NACHIKETA R. 180143106010

2. INTRODUCTION…
■ 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.
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3. OBJECTIVES :-
■ For the gradual introduction Centrifugal force
■ To introduce super elevation gradually
■ To introduce extra widening gradually
■ To provide comfort for the driver that is to enable smooth vehicle
operation on road.
■ To enhance aesthetics of highways.
■ To prevent the possibility of overturning of vehicles on horizontal
curve.
■ To improve in design speed on horizontal curves.
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4. TYPES OFTRANSITION
CURVES :-
A. Spiral or clothoid
B. Cubic parabola
C. Lemniscate
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5. LENGTH OFTRANSION
CURVES:-1.The Rate of Change of Centrifugal Acceleration
■ The rate of change of centrifugal acceleration to be developed
gradually. From this consideration the length transition curve is given
by the following equation:
Ls = 0.0215V³/ CR
Where,
Ls = Length of transition curve in m
V = Speed of vehicle in Km/h
C = Rate of change of centrifugal acceleration
R = Radius of the circular curve in m.
■ The minimum and maximum values of C are limited to 0.5 & 0.8
respectively.
C = 80/(75+V) m/sec3.
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6. CONTINUE…
2.The Rate of Introduction of Designed Super Elevation
■ The rate of introduction of designed superelevation to be at a
reasonable rate. From this consideration the length of the transition
curve is given by the following :
Ls = e.N (W +We)/2
Where,
e =The rate of designed superelevation
W = Normal pavement width in m
We = Extra widening pavement at the circular curve in m.
1/N = Rate of change of superelevation
(Minimum value of N is 150 to 60 ).
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7. CONTINUE…
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3.By Empirical Formula
■ According to I.R.C standards, the length of the horizontal transition
curve should act, then the value given by the following equations:
a)For plain and rolling terrain,
Ls = 2.7V²/R
b)For mountainous and steep terrain,
Ls =V²/R
Hence these are the three criteria to determine the length of
transition curve. The maximum of above three conditions will be
considered as the length of transition curve.

8. THANKYOU !
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