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Calculate Superelevation - Attainment Page

Product Documentation
Intermediate
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Use this page of the wizard to specify the design criteria file, superelevation rate table, transition length table, and the attainment method.

Design Criteria File

Specifies the name of the design criteria file. This file defines minimum radius tables, superelevation attainment methods and formulae, superelevation rates and transition lengths for various roadway types and design speeds. Click to browse to the location of the design criteria file.

Note

The specified design criteria file determines the options that are available in the Superelevation Rate Table, Transition Length Table, and Attainment Method options in the drop-down lists.

Superelevation Rate Table

Specifies the name of the superelevation rate table used to determine the maximum superelevation rate. Click the arrow to display a list of the superelevation rate tables associated with the specified design criteria file.

Note

In the list, choose Superelevation Rate By Formula in situations where you want to calculate the superelevation rate based on a formula rather than a pre-defined table. In the out-of-box criteria files that Civil 3D provides, there is a simple formula based on AASHTO standards that will calculate the superelevation for a given radius and design speed. You can edit this formula to meet the requirements of local agencies that may vary from AASHTO.

Transition Length Table

Specifies the name of the superelevation transition length table used to calculate the transition stations. Click the arrow to display a list of the transition length tables associated with the specified superelevation rate table.

Attainment Method

Specifies the name of the superelevation attainment method. Click the arrow to display a list of the attainment methods associated with the specified design criteria file.

Transition Formula For Superelevation Runoff

Specify the parameter for the transition formula from the criteria file. The percentage that is entered is converted to a decimal percent and used in the formula. If specified design criteria file does not recognize this parameter, this section is disabled. If a curve is preceded or succeeded by another curve, the tangent transition formula is applied.

% On Tangent For Tangent-Curve

Specifies the percent of the transition length that is located on the tangent for tangent-curve or curve-tangent situations.

% On Spiral For Spiral-Curve

Specifies the percent of the transition length that is located on the spiral for spiral-curve or curve-spiral situations.

Curve Smoothing

Apply Curve Smoothing

Select the check box to enable the Curve Length field.

Curve Length

Enter a length value that is greater than zero. This value is displayed in the curve smoothing column of the tabular grid editor. A smooth curve is also shown in the superelevation band and superelevation view at the appropriate critical station.

The following illustration shows an example of the results when you apply curve smoothing.

Automatically Resolve Overlap

Select this check box to automatically detect overlap conditions and eliminate the overlapping stations. All transition stations between the End Full Superelevation station on the first curve and the Begin Full Superelevation on the second curve are removed, for compound or reverse situations. This option is only available when superelevation is applied to the whole alignment.

Note

When this option is selected, corrections are made on all overlap situations. To remove automatic overlap, clear the check box and recalculate superelevation.


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