Modeling Corridor Subassembly Transitions - Retaining Wall End

[ndegan]

When modeling corridors I have always had an issue with how to model a transition in a retaining wall.

The attached image shows a trail corridor. 

• The trail and shoulders are 1 assembly using a centerline alignment as the main baseline.
• The connections to EG (both left and right) are using corridor feature lines as baselines in order to set regions independent of the centerline assembly. This gives more flexibility for placing retaining walls.
  • The shown connections are a link slope to surface at 3:1 and a retaining wall. There is no gap in the regions from 3:1 to retaining wall.
• The entire corridor is 5' of fill above EG. 

I want the retaining wall height to taper from the connection to EG, upward to meet the point where the 3:1 assembly and the wall intersect, at a 3:1 slope. This is a very common occurrence in these types of projects. In the past I have tried a couple things. I've ignored the surface and just drawn polyline contours. I've made a gap in the 3:1 and retaining wall regions, then manually created a transition using feature lines and adding them to the corridor surface. Both of these options require a lot of work and are not dynamic with the corridor. I'm looking for a better way.

I have seen videos from Jeff Bartels showing ways of creating transitions in corridors (links below) but I don't know if I can make these options work for a retaining wall transition of this nature. If someone knows how to make these work in this application, this would be ideal because they would be dynamic with the corridor.

Jeff Bartels Applying Transitions to Virtually Any Civil 3D Subassembly - https://www.youtube.com/watch?v=W-f4Ep7TXyE

Jeff Bartels Modeling a Civil 3D Corridor with Variable Slope Daylight - https://www.youtube.com/watch?v=NKyTjaUL3J0

So my question to everyone is, How do YOU model retaining wall transitions?

[Anonymous]

Try stepping a feature line from the top of the retaining wall either 0.005' or 0.01' and then down the height of the retaining wall and add this feature line to your surface.  I use this format if I need to built surfaces around headwalls at retention basins. HTH

[ndegan]

Thanks Azrdgldr, your suggestion is very similar to the way I currently model these transitions. I'm hoping to find a solution that doesn't require manual feature line creation. Preferably something using the corridor itself.

[cwr-pae]

I think I would model this with a single corridor with daylight. Extract linked FLs from the last link/point of the primary corridor before the daylight link and from the daylight FL. Run a second corridor using the same base line and profile with an assembly configured to target the shoulder FL with an omitted generic link, then another omitted generic link (LinkToOffsetOnSurface) to target the corridor surface and a line tracing the back of the headwall. Then add the subs to model the headwall in this second corridor and close from its lower outer FG intersect to a the FL from the primary corridor daylight line. 

To create the FG surface I would paste the surface from the corridor to a new surface and add linked FLs for the head wall and the headwall daylight extracted from the second corridor. Don't add these FLs to the surface of the primary corridor as it would be loop the would want to rebuild endlessly.

[lynn_zhang]

Hello @ndegan ,

Just checking to see if your problem has been solved. Did you try the suggestions from above? Let us know if you still need help.

[Joe-Bouza]

Something like this?  maybe some marked point  magic OR sac?

[ndegan]

Thanks Joseph - Periodically I do need to make headwalls as you show in your sketch, but I am unfamiliar with the method you suggested. Can you give me any more info on marked points or sac? Or point me in the right direction for my own research?

[ndegan]

Thanks CWR - I think I understood your suggestion and made a very quick and rough model to see how it works (definitely needs more work but the guts are there). 

• The main trail corridor - I removed the walls and just had the 3:1 in the appropriate location. I then added a "linkoffsetonsurface" (with 1' offset) in the location of the full height retaining walls.
• I made a new surface and pasted in the EG then the main trail corridor surface, to give the retaining wall corridor something to target.
• I created a retaining wall corridor using a autocorridor feature line from the shoulder of the main trail surface and had it target the combined surface.
• I created another surface to paste the main trail surface and the retaining wall surface to create a FG surface.

Does that sound like what you suggested?

[cwr-pae]

I would have done the wall as part of the main corridor as an added baseline using the main centerline and offsets, but that's a personal preference thing. If what you have gives what you need then we have a win. 😉

[Joe-Bouza]

Hello Nick

I made a huge assumption based on your image. you have an embankment that daylights several units away from  where the retaining wall is located, presumably near the back of shoulder. The embankment cant just end and have some transition in the wall back by the shoulder. That's where my sketch shows the wall  running out to daylight or near it to transition back to shoulder and the full wall.

I am only diving into SAC so I cant speak with authority, but it is a program that comes with civil3d that allows you to design custom subassemblies. Mark points and lint to mark point are OOTB subs that aid in connecting point on a corridor.

If I thing again, if my transition theory is correct you can add a baseline to the corridor that facilitates what I sketch by adding a wall from daylight transitioning to full height and on its merry way. That is where SAC can help

[Joe-Bouza]

I did not think of that approach. looks good

[ndegan]

CWR - Oh I see now. I think this method works, however it is a lot of work and requires additional surfaces and an advanced understanding of corridors. Which is something I am trying to make simpler for my company. i don't think I'm ready to call off my search just yet.

[ndegan]

Hi Joe, 

Ohhh I guess I didn't make the connection of SAC to Subassembly Composer haha. I have been spending a lot of time in there recently and it is what sparked my desire to make this post. After sitting in @KMercier_C3D Subassembly Composer class at AU2019, I have been trying to build some skills in the program. I made some custom retaining wall subassemblies (I have never been satisfied with the out-of-the-box ones) and while I was saving the world with the new retaining walls, I thought I'd ask how people handle their transitions. 

I found a picture of what I am trying to do. I'm hoping to find a solution with a subassembly that can handle the transitions.

[Joe-Bouza]

Hello Nick

This Allan Gilbert video may be of interest https://www.youtube.com/watch?v=DXZQMP7dUbc

Looking the photo it makes perfect sense. it seem like a condition sub on your shoulder that switches from daylight shoulder to daylight retaining wall would get you there. The A.Gilbert video adds a daylight to the toe of the wall but im sure your can use the idea the have the daylight point follow a feature line or profile that represents the top of slope on the wall like the photo shows.

I guess there is no need for conditional if your split the region

good success

[fcernst]

That's exactly what RetainWallVertical does..

[ndegan]

Hi Fred,

Yes, the default retaining wall subassemblies will taper if the corridor is targeting EG and goes from a section of fill to no fill. 

The situation I am looking at is entirely fill. The example I gave is a trail that is 5' of fill above EG along its entire length, with regions that have 3:1 grading and regions that have retaining walls. I am looking for a way to easily transition the retaining wall up to meet the 3:1 grading. Left as is, they dead-end and the wall is left at 5' tall. I want to taper the wall from 5' tall (where is connects to EG) up to the point where the 3:1 region is.

[fcernst]

If your target surface (EG) is not doing the the 3:1 slope you show in the picture, then you have to create a modified EG that does.

[ndegan]

Fred,

That's still not the situation I am looking at. I need the 3:1 taper in the retaining wall and the 3:1 slope from my corridor to be FG. I don't want to modify the EG in order to make the taper.

I did try something similar to your suggestion, using all proposed surfaces but it is too cumbersome and complicated for my liking. You can see that example earlier in this thread (Message 8). I'm looking for a better solution.

[fcernst]

I don't want to modify the EG in order to make the taper...

 "EG" is just whatever target surface the RetWall subassembly targets... So just create a surface like the picture shows and run the subassembly through it.

[fcernst]

 It sounds like you want the continuous intersection between the vertical and a 3:1 slope projected up form EG.

You could use LinkSlopesBetweenPoints for this. 

Then take this slope intersection concept to SAC and create a wall with thickness and Shape.