Superelevation Overview
Superelevation tools calculate how much banking to apply to curves and spirals in the horizontal alignment to help offset centrifugal force. These commands also compute how the road will make the transition from normal crown to a fully banked curve and back again.
Superelevation can be calculated in two ways:
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Rules-based - using an XML-based rule file, the station and associated cross slopes of the transitions are based on design speed, curvature, and other design parameters. As the design progresses and parameters change (i.e., design speed exceptions) superelevation can be reprocessed to the revised parameter(s).
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Import - using a comma separate values (CSV) file to import the station and associated cross slope of each transition. In this option, the rules are not utilized; the data is simply applied to the superelevation lanes.
The result of superelevation are graphic superelevation lanes with cross slope attributes stored in a DGN file. The superelevation data can be in its own DGN file, or can be drawn into any of the other project DGN files with geometry, corridor, etcetera. This file can be referenced to a corridor model and associated, so the superelevation transitions are incorporated into the corridor model.
Prerequisites
To create superelevation, the following are minimum requirements:
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One Civil horizontal geometry element.
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Superelevation rate and transition values which can be calculated using a Superelevation Rules file or defined in a CSV file and imported.
To add the superelevation data to a corridor, you will need:
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Superelevation lanes.
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Assign superelevation rates and transitions (calculated or imported) to the lanes.
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Corridor whose template has superelevation flags for control points (for association step).
Settings
The following two sets of settings are utilized within the superelevation tools. It is prudent to set them prior to drawing lanes. There are no required values; these are user preferences.
Fill Settings
Located under File > Settings > User > Preferences > View Options - Civil. The Superelevation Settings category has options for controlling display of superelevation lanes. These settings are a user preference and will apply to all files opened by the user.
Option |
Description |
Color Shaded Fill |
Color Shaded Fill Color fills superelevation lanes AFTER calculations are complete. The coloring is hard-coded based on the cross slope: slope < -10% =blue. -10% <= slope <= -0.5% = Calculated color between green and blue. -0.5% < slope < 0.5% = white. 0.5% <= slope <= 10% = Calculated color between yellow and red. slope > 10% = dark red. Based on the side of road, the colors flip. In addition to setting this option, the View Attribute for Fill must also be toggled on. |
Boundaries Only |
In this option, only the outside boundary of each lane is displayed and can be selected. |
None |
No superelevation lanes / edit handlers are displayed, however, they are still in the file. To display them, set to one of the other two options. |
Stationing and Decimal Place Settings
Located under File > Settings > File > Design File Settings, the Civil Formatting category listing has options for controlling display of element handlers. These settings are not unique to superelevation; the same settings are used throughout the Civil products. These settings are file specific and should be set in the seed file so they are automatically propagated to all project dgn files.
Option |
Description |
Station Settings: Format |
Controls the number of places after the delimiter. |
Station Settings: Format Delimiter |
Controls the delimiter, generally the plus (+) sign. |
Station Settings: Precision |
Defines the number of decimal places for stationing. |
Profile Settings: Slope Format |
Used for cross slope edit handlers. Generally, set to percentage for superelevation. |
Profile Settings: Slope Precision |
Defines number of decimal places in cross slope edit handlers. |