Looking for curb and gutter modeling tips for parking lot projects

[dslocum]

Using Civil 3D 2014....

I do a lot of site projects with parking lots. Right now I create a feature line for the edge of pavement from my parking lot linework, then use the stepped offset command to create the gutter and back of curb. However, since these features are independent of each other, it makes revisions very cumbersome. I've tried using gradings but they create a problems also in certian editing situations such as needing to break a feature line.  I would like to hear about how others are modeling parking lot curb and gutter. Would it be easier to use an alignment/ corridor and apply a curb profile? Any tips would be appreciated.

[Citadel2012]

Try creating a broad "general" surface defined by feature lines across the site without regard to parking lot geometry (i.e. ignoring islands and curb returns, etc.). Then you can turn your islands and curbs into alignments and create dynamic feature lines from those alignments that sample the general surface. You can use those feature lines (which are dynamically linked to your general surface) to define a Final surface. Any areas that require more detail can be made into a seperate surface and pasted into the final surface.

[dslocum]

Thanks! I guess I've never used dynamic feature lines before, but I'll check that out. Using this method, how are the feature lines that represent the curb and gutter linked together? or are they still indpendent of each other?

[Neilw_05]

As you noted, the curbs and sidewalks and everything else related to the edge of pavement needs to be tied together. The only tools capable of doing that are gradings and corridor assemblies. There are problems with both approaches. Corridors do not handle mitered corners, transitions and overlaps very well. You've already experienced the problems with gradings.

[Neilw_05]

I should mention that using citadels suggestion to create a base surface, you can use a corrdidor for the edge of the parking lot. The alignment would be the edge of pavement and the profile would be the sampled base surface. The assembly would consist of the curb, sidewalk and daylighting. The entire parking lot would thus be tied to the base surface.

As I mentioned, you'll have problems with mitered corners, transitions and overlaps, but it is an alternative to using gradings.

[sboon]

I like Citadel's idea, and I've been playing around with a variation on his method.

I started with a closed alignment representing the bottom of a wall and an EG surface.  I copied the surface, and raised it by 9'  I then created an offset alignment 0.5' to the inside, representing the back of the wall.  Using those two alignments and surface profiles I can create dynamic featurelines that update whenever the alignment or the original surface changes.

I added two infills to create a surface that shows the face of the wall and the enclosed area.  Note - this just interpolates across the closed area and doesn't necessarily match the original surface below.  I then created an FG surface and pasted the EG and Grading surface into it.

The workflow needs a little refinement but it seems like it would be useful for building subgrade surface, top of islands etc.  I like the dynamic abilities - I can move the alignment, change the offset parameters, raise or lower the top surface and it stays up to date.

Steve
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[Joe-Bouza]

That technique was a reworking of Eric Chappels "Islands of Asphalt". It takes a little up front organization but can make quick work of most grading schemes. And yes it works splendidly for subgrade surfaces.

[jmayo-EE]

First off I agree with the method being recommended and would always recommend using it.

But... if you already have the feature lines set in a project and you do not want to rebuild it with a corridor. The next time the curblines change and you feel the need to delete and recreate the offset, try using the Feature Line Elevations From Reference command to correct the elevations vs rebuilding them.

[dslocum]

That's a great idea. Thanks Mayo!