We are having trouble verifying how StormCad is calculating inlet capture efficiency for Parabolic Street Section. No matter what we input for the crown height, it always calculates the street section with 2% slope. So, for a 13' parabolic street section with a 5" crown, the cross slope of the street section at the gutter should be something greater than 3.21%.
I see that you already have a service request for this and once we come to a resolution with it I will post the answer on the forums.
Regards,
Mark
Hello Minimum System Requirements,
We seem to be having difficulty contacting you via your service request, so I wanted to provide some general feedback on your forum post here based on the information provided.
When you select "Parabolic" for the Gutter Shape of a catchbasin, the program uses the equation listed in the help under "Parabolic Gutter Section", based on the height H and "half width" B
You mentioned that the street section is calculated with a 2% slope regardless of the Height entered. What are you seeing in the model that indicates this? Are you taking the calculated depth divided by the spread? Or, are you possibly looking at the "Road Cross Slope" field in the Catchbasin Flextable? That field is only valid for the Conventional and V-Shaped gutters and will be hidden from the Properties window for Parabolic shaped gutters (and won't be used).
I did some quick checks in one of the sample files, in StormCAD 08.11.03.84 and didn't seem to notice any problems. Based on looking at the calculated depth divided by the calculated spread field, the value is always greater than if you were to take the full height divided by the full width, which makes sense due to the convex shape. I also adjusted the catchment of my test catchbasin until the flow was high enough to result in a depth equal to the parabolic gutter height, and the resulting spread was exactly equal to the entered parabolic gutter width (half width B). I tried this with two different cases: 0.5' height / 13' width and 1.0' height and 13' width.
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Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.