Module 3: Geometric design of highways

Lecture 16 Horizontal alignment III

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Problems

1. Calculate the length of transition curve and shift for V=65kmph, R=220m, rate of introduction of super elevation is 1 in 150, W+We=7.5 m. (Hint: c=0.57) [Ans: $L_{s1}$=47.1m, $L_{s2}$=39m (e=0.07, pav. rotated w.r.t centerline), $L_{s3}$=51.9m, s=0.51m, $L_s$=52m]
2. NH passing through rolling terrain of heavy rainfall area, R=500m. Design length of Transition curve. (Hint: Heavy rainfall. Pavement surface rotated w.r.t to inner edge. V=80kmph, W=7.0m, N=1 in 150) [Ans: c=0.52, $L_{s1}$=42.3, $L_{s2}$=63.7m (e=0.057, W+We=7.45), $L_{s3}$=34.6m, $L_s$=64m]
3. Horizontal curve of R=400m, L=200 m. Compute setback distance required to provide (a) SSD of 90m, (b) OSD of 300 m. Distance between center line of road and inner land (d) is 1.9m. [Ans: (a) $\alpha/2\approx6.5^{o}$, m=4.4 m (b)OSD$>$L, for multi lane, with d=1.9, m=26.8 m]