Safe Length of Crest Curve
Safe Length of Crest Curve
- To determine the curve safe length:
- compute the SSD, or use tables, according to design conditions.
- Apply one of the formulas, neglecting (A)sign:
- Lm = 2 SSD - {200( H1- H2)2/A} Substituting for H1 = 1.07m and H2 = 0.15m get Lm = 2 SSD - (404/A) if SSD>L
- Similarly, Lm = A (SSD2/404) if SSD < L
- Always assume SSD < L first, then check the answer.