This is a real doozy my boss wants done. We have and existing sewer lagoon with 4:1 side slopes. We are designing a bypass pipe outside of the 4:1 side slope but because of cover issues, we need to add some dirt to the side slope to fill above the pipe. He wants to continue that 4:1 side slope up until it matches the profile elevation abaove the pipe. Once that happens, then grade a 12' wide berm with 2% crown each way and then come back down the other side at a 4:1 until it matches existing grade. We drew a target line at the tope of the existing 4:1 on the existing ground and used that as a start point.
Here is the problem, we are using the "linkwidthandslope" sub-assembly, how do we tell it to go up at a 4:1 until it matches our design profile grade? Horizontally, that right side of the sub-assembly wil be different in every cross section,but vertically it needs to match the profile. The left side of the sub-assembly is working okay and tieing in at the top of the existing 4:1 slope. The right side of the sub-assembly though is tieing in at the design profile grade vertically and at the alignment centerline horizontally. When this happens, my slopes all differ and they cant, they need to go up at a 4:1 so the existing 4:1 slope continues going up.
Does this make sense to anyone? Its a tough one.
Attached are some pictures.
Having some trouble following, I think more pictures might help.
Isn't it possible to give a target profile without targeting an alignment? Use a link at a specified slope (4:1) targeting the design profile.
Mark Green
Working on Civil 3D in Canada
I have targets set up to a feature line in which the left side of the sub-assembly ties into. This is at the top of the existing berm. The problem is, why does the right side of the sub-assembly autommatically tie into the profile design grade? Is the "linkwidthandslope" sub-assembly the wrong one to be using?
It looks to me as if you have a slight crown (2%?) and then the right side is targeting the surface at 4:1. Is that not what's happening? It looks like it starts at the bottom of that 2% and then targets the surface. What do you want it to do?
In your first message, here is an intersting line:
"He wants to continue that 4:1 side slope up until it matches the profile elevation abaove the pipe."
So, you want to start at the existing top of 4:1 slope (horizontal and vertical requirement)
You want to end at the profile elevation (vertical requirement)
You want to end above the pipe (horizontal requirement)
It sounds like you have horizontal and vertical requirements for the bottom and top of this slope, so how can you also give it a slope requirement (4:1)? Unless you give the top the freedom to move horizontally so as to be not above the pipe, it can't calculate the slope.
Mark Green
Working on Civil 3D in Canada
Troma laid it out correctly. Yes, I want to continue that existing 4:1 slope up on the left side until it matches the elevation of my design profile. With that being said, the horizontal location of where that 4:1 slope will stop varies because my design profile drops at 0.570%. If you look at the .pdf I attached earlier, you can see that the red dot where it is supposed to stop is actually right of the centerline. The offset at which it stops though in each cross section will vary since the existing top of the 4:1 slope varies in distance from my alignment centerline.
Lisa, good thought but the "linkslopetoelevation" want a constant elevation to project up to. In my case, the 4:1 slope needs to continue project up until it meets the design profile elevation at that particular cross section.
Once that happens, I will then attach "linkwidthandslope" sub-assemblies to creat a 12' wide berm and then tie back into the existing grade.
The right side is working fine.
If you can picture this correctly, when it works, the new pipe (which is down the center of my alignment) will run somewhere under the 4:1 side slope that is being continued up. The center of my new berm will float from left to right over the pipe and alignment centerline.
How are the targets programmed to work? Does it assume that if your sub-assembly is on the left side of the baseline that the left point code of the sub-assembly is what gets targeted to your target lines and vice versa, if your sub-assembly is on the right side of the baseline then the right point code of the sub-assembly gets targeted to your target lines?
Thats what it is doing in this case, the left side of my "linkwidthandslope" sub-assembly is targeting my target line which is good but the right point code just defaults to the design profile elevation at centerline. I really want that right point code to keep going up at a 4:1 to the same elevation of the profile.
As I understand it, the whole assembly needs an alignment & profile to start from. It can then target other alignments & profiles as necessary, or not. If the one point that is absolutely concrete is the top of the existing berm, you need an alignment and profile running exactly along the top of berm. (Alignment tracing the top of berm, profile from surface.) That should be the anchor point of your assembly. You will need to target the other profile with a 4:1 slope for starters, then put your 2% crown, then matching existing the other side.
If you use the pipe alignment as the anchor point it can't work, because it is anchored horizontally to that location.
Mark Green
Working on Civil 3D in Canada
You could do it piecewise.
You first goal is to find the meandering alignment for the red dot, located vertically at the desired pipe cover profile elevation, correct?
Fred, it's simpler than that. It's just a matter of priorities. You need to build the assembly with the same priorities as you want the berm to have.
1. You start from the top of existing berm.
2. Go up at 4:1 until you hit the profile elevation. (you may have to superimpose the design profile onto the profile view of the 'top of berm' alignment)
3. Go up at 2% whatever distance.
4. Go down at 2% whatever distance.
5. Go down at 4:1 until you hit the existing ground.
Mark Green
Working on Civil 3D in Canada
would this work:
1. create a grading from Existing top of slope at 4: for an arbtrary distance.
2. create a FL from you desing profile add a horizontal grading to intersect grading 1.
3. now you can target grading 2 daylight point and continue from there
Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
Hey Troma,
I think you and I are on the same page. I have a 3d polyline on the top of my existing berm at elevation so yes in deed, the left anchor point is targeting that and it shows up correctly in my cross sections. But my problem still is getting the other end (right side) of my sub-assembly to target that profile elevation. I can't fugure out how to tell the sub assembly to do that. So, because of that, the right side of the sub-assembly just targest the centerline at the design profile elevation.
Joe,
I understand what you are saying here. It will creat and intersection point that meanders around. I understand what your saying but actually doing it is another thing. I have not worked a whole lot with grading objects. How ould you do this?
You're right.
You could do it starting with the Subassembly.LinkSlopeAndVerticalDeflection coming up from the existing toe on the left, targeting his pipe cover profile.
Taneum, my point is you can't use the top of berm as a target!
You must put an alignment and profile on the top of berm, and use it as the start point for the assembly. Then all the subassemblies are to the right. Read over my last post again.
Mark Green
Working on Civil 3D in Canada
I think we are all on target with this design, but if the "design grade" is above the pipe and a 4:1 elevation target is on the right side of the "design grade" then the cover requirement is being violated. No?
Not to criticize the design but if cover is this tricky on a 4:1 then IMHO the pipe alignment should be moved further from the edge of embankment
Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
It sounds to me like troma basically has the right idea.
You want to start building from the featureline that you've already drawn along the top of the existing berm, but this is probably a meandering line that wouldn't be very suitable for a baseline alignment and profile. None of your sections would be parallel and the corridor would be messy to work with. I would suggest that you use the pipeline as your horizontal alignment and have two profiles for it. One is the pipeline invert, used only for the corridor baseline. The other one is the controlling elevation for your red dot.
Starting from your baseline point add a generic LinkOffsetAndElevation which will be targeted both horizontally and vertically to your featureline on the top of existing berm. From there you can use LinkSlopeToElevation to the top of your new berm with a target tied to the upper profile you've built. From there you can add lane subs to create a finished top of the new berm or you can just use DaylightGeneral to finish the whole thing in one step.
"How about a LinkSlopeToElevation link instead?"
No, looking back at the thread now, Lisa had it first!
I was looking at this again and thinking that it would be better to have the corridor following the berm. I think that it will make it easier for building sections, and for survey layout later.
What I did was to build an alignment and baseline profile at the crown of the berm. My assembly uses LinkOffsetOnSurface (with the hide link option turned on) to place marked points at the two daylights. I then used LinkSlopeBetweenPoints to create the top and side of the berm. This workflow alllows for a different way to control the berm size and shape but produces pretty much the same result.
Nice.
This is a greatly helpful demonstration of some creative techniques working together (hide link, LinkSlope BetweenPoints clean up).
The only thing about this option for this scenario, is that I think he wants his berm's top left edge pushed over at 4:1 up to the pipe cover profile elevations, and then created 12' wide, crowned 2% symmetrically.
Can't find what you're looking for? Ask the community or share your knowledge.