Civil 3D Curb Return Profile Design

November 25, 2020 Scott Kraner

The Civil 3D Create Intersection Wizard can be used to quickly produce the complex corridor models, which comprise intersections, with automatically generated curb return geometry.  However, this curb return geometry does not always meet design requirements.  It is often necessary to use a more complex curb return profile than the single, straight grade provided by the Wizard.  This is particularly true when curb returns need to accommodate drainage structures or ADA ramps, which require precise elevations at specific locations along these profiles.  These requirements do not necessitate a return to manual intersection creation methods, however.  Instead, the Create Intersection Wizard can be used to create the initial Intersection object, as shown in the image below.

Note: The corridor’s Code Set Style does not display the corridor section links or several feature lines.  Some additional geometry and topographic elements, such as off-set alignments, have also been turned off.  This is intended to reduce clutter in the images included within this article.

To prevent the Create Intersection Wizard from attempting to overwrite the modifications that will be made, we will need to delete the intersection object from the drawing.  Selecting and deleting the intersection marker removes the intersection marker from the drawing area and its folder from the Prospector tab of Toolspace, as demonstrated in the images below.  Note that the intersection label is also removed.

Although the intersect has been removed, the corridor regions automatically created by the Wizard remain (see image below).

A special label set with closely spaced station labels can be created and used on the curb return alignment to facilitate the location and layout of curb ramps, drainage facilities, and other design elements along the curb.  The image, below, includes station labels set to a 10-foot interval for major stations and a 2-foot interval for minor stations.  However, these intervals can be adjusted in the label set, as needed.

Station/offset labels can also be placed to determine precise locations of points along the curb return requiring specific elevations to be set (see image below).

Once locations are determined, a profile view can be created for the curb return profile.  The automatically generated profile can be analyzed at critical points using station/elevation labels and the entire profile design can be viewed and analyzed using the Profile Geometry Editor (see image below).