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Table Of Contents
Chapter 3 Working with Profiles and Vertical Alignments
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NOTE
If you do not see the graphic representation of the curve type you want to
create, then click the Next or Previous button at the bottom of the Vertical
Curves dialog box.
3 Select the tangents that represent the grade coming into and out of the PVI.
4 Enter the horizontal length of the curve by typing a value or by picking two
points in the drawing.
The following illustration shows a vertical curve based on the curve length:
Drawing a vertical curve by length
Drawing a Vertical Curve Based on a
Minimum K Value
One method of drawing a vertical curve is to specify a K value. The K value of a
vertical curve is the horizontal distance required to affect a 1% change in grade
on the vertical curve. (K = Length of curve / (|Grade in| - |Grade out|).
To draw a vertical curve based on a minimum K value
1 From the Profiles menu, choose FG Vertical Curves to display the Vertical
Curves dialog box.
2 In the Description list, select the K Value option. You can also click the K Value
icon, and then click OK.
NOTE
If you do not see the graphic representation of the curve type you want to
create, then click the Next or Previous button at the bottom of the Vertical
Curves dialog box.
3 Select the tangents that represent the grade coming into and out of the PVI.
4 Enter a minimum K value.
This command calculates the necessary length of curve for the given minimum
K value, and displays the value at the Length of the curve prompt.
5 Press ENTER to accept the length of curve for the given minimum K value, or
type a new value.
If you enter a new length, the command recalculates the K value and draws the
curve with the specified length.