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 r sign:
- Lm = 2 SSD - {200( H1- H2)2/r} Substituting for H1 = 3.5 and H2 = 0.5 get Lm = 2 SSD - (1329/r) if SSD>L
- Similarly, Lm = r SSD2/1329 if SSD < L
- Always assume SSD < L first, then check the answer.
Notes:
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