Question

A state highway passing through a rolling terrain has a horizontal curve of radius 400 m . If the design speed of the pavement is 80 kmph, width of the pavement at the curve is 7.8 m, rate of change of centrifugal acceleration is 0.52 then the length of transition curve required so that rate of change of centrifugal acceleration is developed gradually and is as per IRC is

Answer 1

Length of transition curve from

(A) Rate of change of centrifugal acceleration =

$\frac{V^3}{CR}=\frac{(0.278\times 80{)}^3}{0.52\times 400}=52.88m$

(B) $IRC=\frac{2.7V^2}{R}=\frac{2.7\times {80}^2}{400}=43.2m$

Hence the length of transition curve required is maximum of above two = 52.88 m say 53 m