Understanding Vertical Curve Calculations
Vertical curves are parabolic curves used in road and railway design to smoothly transition between two grades, ensuring safe and comfortable travel. This calculator computes the elevation at a specific point along the curve.
The formula is y = g1*x + (r*x^2)/2 + E_pvi, where g1 is the initial grade, r is the rate of change of grade (r = (g2 - g1)/L), x is the distance from PVC, and E_pvi is the PVI elevation.
Vertical Curve Elevation Examples
| Initial Grade (%) | Final Grade (%) | Curve Length (ft) | Distance from PVC (ft) | Elevation (ft) |
|---|---|---|---|---|
| 2 | -1 | 400 | 200 | 1002.5 |
| 3 | 0 | 600 | 300 | 1012.5 |
| 1 | -2 | 500 | 250 | 998.75 |
How to Use the Vertical Curve Calculator
- Enter the initial grade (g1, in %) of the curve.
- Enter the final grade (g2, in %) of the curve.
- Enter the curve length (L, in feet or meters).
- Enter the PVI elevation (in feet or meters).
- Enter the distance from the PVC (point of vertical curvature) to calculate the elevation.
- Select the unit (feet or meters).
- Click "Calculate Elevation" to see the elevation at the specified point.
Vertical Curve Elevation Profile
Elevation along a vertical curve (g1=2%, g2=-1%, L=400 ft, E_pvi=1000 ft).
Frequently Asked Questions
What is a vertical curve used for?
Vertical curves provide smooth transitions between different road grades, improving safety and comfort in road or railway design.
How is the rate of change of grade calculated?
The rate of change (r) is calculated as r = (Final Grade - Initial Grade) / Curve Length, expressed as a percentage per unit length.