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Table Of Contents
Calculating Culvert Size and Shape
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6 In the Diameter box, type a diameter for circular culverts, or a height for box
culverts.
You can also click Select and select a diameter height from a data table. The data
table comes with preset settings that you can customize.
7 In the Width box, type a width for the box culvert.
You can also click Select and select a width from a data table. The data table
comes with preset settings that you can customize.
NOTE
This edit box is not available if you selected Circular as the culvert barrel
shape.
8 In the Flow box, type a peak discharge value for the culvert.
You can also click Select to display the Runoff Editor dialog box.
9 In the Mannings n box, type a Mannings n roughness coefficient for the
culvert.
You can also click Select and select a coefficient from the Culvert - Mannings n
dialog box. This dialog box displays a description of the culvert material and the
roughness coefficient value of the material.
10 In the Roadway Elev box, type a roadway elevation for the bank above the
culvert.
You can also click Select and define the elevation by selecting a point on the
roadway in your drawing.
NOTE
A surface from which to extract the elevation must be set as current in the
drawing, or you must use an object snap when selecting the point from a
3D object.
11 In the Inlet Elev box, type an inlet elevation for the culvert.
You can also click Select and define the elevation by selecting a point on the
inlet in your drawing.
NOTE
An AutoCAD Land Development Desktop surface from which to extract the
elevation must be set as current in the drawing or you must use an object
snap when selecting the point from a 3D object.
12 In the Outlet Elev box, type an outlet elevation for the culvert.
You can also click Select and define the elevation by selecting a point on the
outlet in your drawing.
NOTE
You must set a surface from which to extract the elevation as current in the
drawing or use an object snap when selecting the point from a 3D object.
The following values are calculated by the program:
n
Headwater: The calculated headwater for this culvert
n
Slope: The calculated slope for the culvert
n
Velocity: The calculated velocity for this culvert
13 To include roadway overtopping values in the culvert calculation, click the
Over-Top button.