Corridor Template - Issue Modeling Subgrade - Inside Curve and Side slope

I am modeling a subdivision road and trying to use a hybrid of tools to create a complete takeoff.

I modeled the pavement and shoulders with the vertical design tool, slopes and ditches with existing contours and breaklines and applied msi materials to create subgrades. In fill sections of the road, I am using the corridor template to create a small model to represent the extra selects that would be installed for daylight selects. I did this using the side slope instruction to “hit” the modeled subgrade. This worked pretty well but I am seeing an issue on inside curves of the alignment.

I believe this is a TBC bug.

Sewall 5.32.vce (2.6 MB)
217424 - Full Set NH-705 6-6-17.pdf (9.5 MB)

I am seeing similar results when I try and use the surface tie command as an alternative solution. The surface tie seems to be a little more densified but still has issue on the inside curve.

Perhaps an issue with how this tie is calculated.

Corridor Template Surface

Surface Tie

Hey Patrick,

Could I get you to upload your supporting project folder? This folder will have the same name as your vce and is stored in the same directory. Also could I trouble you for a pdf plan set?


Shane Odenbach

Here is the folder:Transfer - Dropbox It looks like you cannot upload a folder or a zip file

Varying Slope:
I used the slope by depth to create conditions for whether the subgrade needs to daylight or is in a box situation. I am seeing the same behavior on the inside curves.

I am not sure if this is the best approach but it seems to work pretty well.

Is there a way to create a shareable slope by depth table? I could see this being very useful.

I found the problem. It was because on the sharp, inside curves, the node was within the subgrade box. I offset this by .01 (outside of the box) and everything worked like it should. This is probably because of the ~.01 wedge that is created when applying subgrade areas.

Not Working:



I have found that to be the issue along curves in the roadways. I would always use 2d lines to stop my instruction slope and would always have blanks in my finish surface because my surface was created in straight segments and no curve segments. It took me sometime to figure this issue as you have encountered. I one day zoomed in as much as i could on the area where i was getting blanks in my surface and found my surface was crossing over my 2d lines. So, what I did was as you did i offsetted my back of curb line about 0.10’ or more depending if that was not enough. Then i would just add a connect instruction to fill in the gap.

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Seems like a tolerance issue with curves.

In my case, to close the gap, I think I am going to use the side slope command in reverse back to the subgrade box because then I can create a somewhat generic template that I can reuse.