Retaining Wall Modeling

[Anonymous]

I have a series of floodwalls and underground concrete utility troughs that I am trying to model and would like to have them all in one surface to check for conflicts and established concrete quantities. What would be the best way to do this? If you create corridors and assemblies can you pull the complete surface for the wall out of it? I don't see a way to do this and have the complete wall shown in a surface.

[doni49]

You could use featurelines:  one for the ground line & top of wall at each side of each wall.  Just make sure the tops are stepped back from the bottoms (I typically use a slope of 10000%).  Then use them in your surface definition.

[jeff_rivers]

I model walls using assemblies made up of link-width-and-slope subassemblies to get the footing excavation volumes, the footings, the wall faces, and the tops of the walls.  

As Don mentioned, C3D does not allow surfaces to contain different points with the same X and Y coordinate but different Z coordinates.  So you need to batter the face of wall a small amount, say 10,000%, in order that a point on the top of the wall does not sit exactly on top of a corresponding point at the base of the wall.  

Same for your utility conduits, you can't model them with vertical side walls, they will have to have a slight slope.  

For that reason, I don't think you'll be able to make one surface that contains everything.  Without knowing more I see at least a couple surfaces, there will be a datum surface and a top surface, from which you can get the concrete quantities for the utility conduits and for the walls, as well as a total material excavation quantity.  

If the utility conduits pass below the walls anywhere then things will get complicated, necessitating separate top and datum surfaces for the walls and the utility conduits.  

[Anonymous]

Thanks Guys for the input, appreciate it.  This one is giving me a little bit of trouble.  So what I have is a simple I-Wall which I drew a subassembly for and created a corridor along the top of wall.  The I-Wall is a simple 120' in length and 10' in height wall with top elev at 15 and bottom elev at 5 with about 4' above ground.

I am having a heck of a time pulling the surface from the corridor? It sounds like it is because when I drew the subassembly I made the walls perfectly vertical when they need to have a very small batter for Civil 3d to recognize them? 

Another question, how critical are the Code Sets?  I don't use corridors much.

[doni49]

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@Anonymous wrote:

Thanks Guys for the input, appreciate it.  This one is giving me a little bit of trouble.  So what I have is a simple I-Wall which I drew a subassembly for and created a corridor along the top of wall.  The I-Wall is a simple 120' in length and 10' in height wall with top elev at 15 and bottom elev at 5 with about 4' above ground.

I am having a heck of a time pulling the surface from the corridor? It sounds like it is because when I drew the subassembly I made the walls perfectly vertical when they need to have a very small batter for Civil 3d to recognize them? 

Another question, how critical are the Code Sets?  I don't use corridors much.

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That's definitely the first thing I'd look at.  When you stop to think about how triangulation works, it makes perfect sense as to why two points at different elevations can't occupy the same horizontal location:

The surface consists of a bunch of triangles and each of the three points has ONE elevation.  The line between two of those points allows the computer to interpolate the location between the points at which a given contour would cross the line.

If the same horizontal location had TWO ELEVATIONS, which one should/would it use for the triangles?

[fcernst]

The software is designed such that corridor Material quantities like concrete are generated from the subassembly shape for the concrete structure. Surface comparisons are for subgrade earthwork, muck and rock excavation quantities.

[jeff_rivers]

Yep, you are on the right track.  Adjust your subassemblies so that the wall has a slight batter.  Next define two codes, Top and Datum.  

In a corridor the Datum represents the lowest elevations of the corridor, or in other words, the depth of the excavation needed.

The top code represents the top of the structure (wall) or top surface of the road (pavement).  

Look at one of the road subassemblies (such as Pavement Superelevation AOR) to see where the Top and Datum codes are placed on a typical road assembly, that will guide you for placing your Top and Datum codes.  

Once you get your corridor working and you can create surfaces, create a Top surface defined from all the Top points, then create a Datum surface defined from all the Datum points.  Finally make a Volume surface that is defined by the Top and Datum surfaces.  That volume surface will be the volume of concrete necessary to construct the wall.  

Also from your Datum surface you can compare it to existing ground to get a volume of excavation required.  

Forgive me if this is too wordy and you know how to do these steps, it's hard to tell what a person's experience is from just a few posts on the forums.