Vertical Alignment Options

Use these options to define each curve at a Point of Vertical Alignment (PVI) in a vertical alignment (VAL). They are available on the Vertical tab of the Alignment Editor.

Note: The input modes are defined in Project Settings, which can be accessed by clicking the Project Settings icon in the editor.


Options
PI Type	POB (Point of Beginning) - This denotes the starting point for an alignment. Define it by entering the station and elevation. Grade break - Select this to define a point of vertical intersection (PVIs) that does not have a curve by entering the station and elevation where the grade changes. Typically, this is used for small changes in grade, or for the end of the vertical alignment. Symmetrical vertical curve - Select this to create a vertical curve when the curves on either side of the point of intersection (PI) are of equal length. Define it by entering the station and elevation of the PI, as well as the curve length (the K factor is calculated). Asymmetrical vertical curve - Select this to create a vertical curve when the curves on either side of the point of intersection (PI) are of unequal length. Define it by entering the station and elevation of the PI, as well as the approach and departure curve lengths. Vertical arc - Select this to enter a vertical curve with a constant radius. Define it by entering the arc midpoint’s station and elevation, as well as its radius. End of symmetrical curve – Select this to create a vertical curve that is defined by the point of tangency (PT) at the end of the curve, rather that its PI. Define it by entering the station and elevation of the PT, as well as the radius.
Station	Type a station value, or pick it in the profile view.
Elevation	Type an elevation value for the station, or pick it in the profile view.
Curve Length	Type a length for the vertical curve, or pick two points in the profile view to use the distance between them as the length.
Radius	Type a radius value for the arc.
K Factor	This displays the calculated ratio of change on the vertical curve.
Approach Curve Length	For asymmetric curves, type a value for the curve before the PVI. (from PVC to PVI)
Departure Curve Length	For asymmetric curves, type a value for the curve after the PVI. (from PVI to PVT)

Note: You can use the same station value for two consecutive PVIs (not just 0+00). This allows a vertical rise or fall in the alignment.

For example, if you need to model channel (drainage) flow-lines where you have a vertical drop, you can add the same station at different elevations.

Station Elevation

2+25.00 125.00

2+25.00 120.00

This will draw the profile to elevation 125 when coming from the station back, and elevation 120 when going towards the station ahead. The order of the entries in the editor determines the order in which they are used.