Module 3: Geometric design of highways

Lecture 17 Vertical alignment I

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Problems

1. A vertical summit curve is formed by $n_1=+$3.0% and $n_2=-$5.0%. Design the length of the summit curve for V=80 kmph. (Hint: SSD=128m). [Ans: 298m]
2. $n_1=$=1 in 1-, $n_2=$ 1 in 120. Design summit curve for V=80kmph, OSD=470m. [Ans: L=417m]
3. $n_1=+1/50$ and $n_2=-1/80$, SSD=180m, OSD=640m. Due to site constraints, $L$ is limited to 500m. Calculate the length of summit curve to meet SSD, ISD and OSD. Discuss results. [Ans: L for SSD=240m, okay, L for OSD=1387m, $>$ 500m not ok, L for ISD=439m ok.]