T-intersections & alignments

[deltacoolguy]

T-intersections & alignments - Is there a better way...?

When making a T-intersection you have to have the alignment of the ending road start/end right at the intersection.  If there's extension the program automatically creates a full 4-way intersection.  I like to have my alignments start/end about 100' beyond the intersection for stationing purposes for staking & construction.

I tried having two alignments for the ending road, one for the corridor and one for reference for plan & staking purposes.  Didn't work.  The program referenced all three alignments and went ahead and made the 4-way intersection.

The only way I can think of working around this is to create, in a separate drawing, a reference-only alignment that extends as I need, then use that reference-only alignment for plan sheets, profiles, etc.

Is there a better way?  How do you work around this?

[tcorey]

You can build your intersection "manually" as part of a corridor instead of using the intersection wizard. It's Civil 3D old-school, but it works and it will allow you to have any overlaps you desire.

[wfberry · Accepted solution]

Tim:

I was going to say the same thing.  While you posted, I ran across this:

https://faculty.unlv.edu/jensen/CEE_301/pdf/AU2008/AU08-CV110-2L_Corridors_Ten-Easy-Steps.pdf

Bill

[Neilw_05]

Why not use the wizard and then delete the parts you don't need?

[deltacoolguy]

---

@wfberry wrote:

Tim:

I was going to say the same thing.  While you posted, I ran across this:

https://faculty.unlv.edu/jensen/CEE_301/pdf/AU2008/AU08-CV110-2L_Corridors_Ten-Easy-Steps.pdf

Bill

---

Looks interesting.  I never did the "old school" approach for intersections.  At first glance it looks longer, but after you factor in all the tweaking you have to do with the wizard, maybe it's not longer.

[deltacoolguy]

A few questions for future reference...

1)  I am presuming this also works for 4-way intersections, correct?  I cannot think of why it wouldn't.

2)  Can this method be used for corridors & intersections that have already been done using the intersection wizard, but still aren't quite right?

3)  If you have a long road with multiple intersections, would be be acceptable to creat a single long alignment and original (primary) corridor, then  break it up into regions and insert your intersection work?  Or, does it work better to create each region separately?

Thanks.

[Joe-Bouza]

Good observation 🙂

[Joe-Bouza]

1. That methos works for all configurations.
2. don't know havent tried
3. yes.
3'. if I wnat to hold the crown of the primary I like to use a conditional sub to illiminate the curb and sw through the intersection and create a separate corridor for the side roads that target the flow line FL extracted from the main corridor

[Joe-Bouza]

I still like to use the intersection to simply to lock the profiles

[deltacoolguy]

Finally got back to this project.

I (re-)did one intersection the "old school" way, and it worked and I will say I like it better.  It's a little tedious, but not bad, really.  I actually kind of like the process because it makes me think and verify things are right as I go along.

I did start a new corridor as it wasn't that long and I was concerned it wouldn't go well.

Thanks for everybody's help, and now I'm off to do the next intersection.

[Joe-Bouza]

Much of the tedium can be averted by taking advantage of loading multiple targets in the first quad and matching parameter for the next

[Steenix]

I've recently been trying to make a tee-intersection with crossing alignments as well. I referenced this thread: http://forums.autodesk.com/t5/AutoCAD-Civil-3D-General/Create-T-Intersection-with-X-Alignment/td-p/3...

I created the offset alignments, and updated all of the parameters in the intersection wizard accordingly. However, the "Corridor Regions" tab is entirely grayed out when I do this. If I press "Create Intersection" CAD returns the message "You have not assigned offset profiles for one or more user specified offset alignments." I haven't noticed an option for assigning profiles to offset alignments, and I thought the lane slope parameter was what took care of this for us (I have "Use an Existing Profile" set to "no" on the lane slope parameters). Am I missing something?

Edit: I should mention I want my end product to be a corridor surface, and I am trying this in Civil 3D 2015

[Joe-Bouza]

You are tripping me up here, Steenix? previously you said you were building them manually and now you are using the wizard? which is it? can you post a drawing for a look see?

[Steenix]

Sorry for the confusion, I should have been more clear. It's kind of a half-and-half deal - I create the offset alignments manually, then have the intersection wizard do the rest. In the thread I linked to previously, Neil said:

"When I tried this it worked fine for me. I created the crossing alignments and then created offsets using the Offset Alignment tool. For the side street I ended the offset alignments at the intersection. When running the Intersection Wizard it offers curb return parameters for 4 corners but it only creates the 2 at the side street."

So I did just that. I created four offset alignments manually, then ran the intersection wizard. In the Offset Parameters options of the Geometry Details section, I selected my newly-created alignments. Doing so caused the wizard to be unable to create a corridor, for some reason.

I have attached the drawing, as requested. I placed a "circle" around the intersection of interest.

Thank you so much for your help.

[Neilw_05]

I looked at your file and I found I can create the intersection fine with the wizard. To get it to work I didn't use the offset alignments since C3D wants those to have profiles. Instead use the parameter option. Once the intersection is created, delete the unwanted curb return alignments and then build the corridor. It should give you a T intersection.

[Steenix]

When you say to delete the curb returns, do you mean I need to go into the corridor properties and delete the curb return sections from there? Or do I just need to delete the alignments?

[Neilw_05]

By the way, your curb return assemblies as defined will not work properly because you used a basic lane subassembly which does not support a target alignment. Thus it cannot be made to stretch to meet the centerlines of the roads. Instead try using the BasicLaneTransition subassembly or one of the others that support target objects.

[Neilw_05]

Just delete the alignments and then recreate the corridor. You will get a prompt to recreate the missing alignments when recreating the corridor. Just say no and you should get the desired results.

[Steenix]

Awesome! Thank you very much Neil, I really appreciate it.

[Neilw_05]

I couldn't get the basiclanetransition subassembly to target the alignments. I've never used it for this scenario so I don't know why. Rather than fight it just use one of the superelevation lane subs.