AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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Neilw
Posts: 2,251
Registered: ‎09-04-2006
Message 1 of 44 (1,021 Views)
Accepted Solution

Tiered wall assembly

1021 Views, 43 Replies
04-02-2012 12:31 AM

I am wanting to model a tiered retaining wall with 5' high tiers, 10' apart at 2% grade between tiers. My strategy is to use a corridor with an assembly consisting of a retaining wall subassembly, a conditional cut/fill subassembly and either a daylight or a bench and another tier depending on the cut/fill condition (see attached image).

 

The problem I am having is the wall subassembly seems to require a target for the height. The help file indicates the height target is optional, so I expect that if I set the target to none in the corridor target settings, the wall height parameter in the subassembly will be used. When I do this the wall does not build. The only way to get it to build is to assign a height target. The only target I have is the existing ground surface and if I use that then the wall projects to EG at the first tier and thus no benching.

 

Can this approach be made to work without having to create some sort of height target? I'm atttaching the assembly (2012 version) for evaluation.

Neil Wilson (a.k.a. neilw)
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jmayo
Posts: 2,798
Registered: ‎11-13-2006
Message 2 of 44 (994 Views)

Re: Tiered wall assembly

04-02-2012 06:29 AM in reply to: Neilw

You can set up linkwidthandslope subs to form a uniform hgt wall. A 4 foot high wall with a 12" top would need a sub for the face of wall with a width of .1, a slope of 400% and a sub for the top of wall, width .9 and zero slope.

 

You can make a sub from a pline and there is also the subassembly composer at autodesk labs.

John Mayo, PE
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Neilw
Posts: 2,251
Registered: ‎09-04-2006
Message 3 of 44 (986 Views)

Re: Tiered wall assembly

04-02-2012 07:25 AM in reply to: jmayo

Thanks for the suggestion John. Before going that route I'd like to know if the wall subassembly can work, partly because it would be easier to tweak the parameters to fit varying conditions. Did you get a chance to look at the assembly? It may be that it is just not set up properly.

Neil Wilson (a.k.a. neilw)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
HP Pavillion h8xt, i7 2600, 12 GB
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http://www.sec-landmgt.com
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peterfunkautodesk
Posts: 715
Registered: ‎08-25-2009
Message 4 of 44 (977 Views)

Re: Tiered wall assembly

04-02-2012 07:33 AM in reply to: Neilw

Neil,

 

The wall that ships was designed to go from the attachment point to a surface, with the profile for the height as an over rule. If you don't have the surface set, you won't get a wall.

 

If the walls are all the same, you might just go with a polyline SA and then the conditionals. Another way would be to make a wall in Subassembly Composer that could also do the conditional tests. I might construct one that does a wall and bench/daylight and then stack a bunch of them together (we don't allow loops in SAC because of the problems that those could cause).

 

Cheers,

 

Peter Funk

Autodesk, Inc.



Peter Funk
Autodesk, Inc.

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Neilw
Posts: 2,251
Registered: ‎09-04-2006
Message 5 of 44 (968 Views)

Re: Tiered wall assembly

04-02-2012 08:04 AM in reply to: peterfunkautodesk

Thanks for clarifying that Peter. I'll give up on the wall SA. It would have been nice to have all the codes and links if it worked but I don't know that I'll need them. I might get by with just a benched daylight SA.

Neil Wilson (a.k.a. neilw)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
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Neilw
Posts: 2,251
Registered: ‎09-04-2006
Message 6 of 44 (924 Views)

Re: Tiered wall assembly

04-08-2012 02:36 PM in reply to: Neilw

I am re-visiting this post after putting this little task on the back burner, as I've not found a solution.

 

I've attempted to solve it using both gradings and a corridor, neither of which give satisfactory results.

 

My objective is to model a tiered wall with 5' maximum tier height, 10' separation between tiers and 2% bench slope. The teirs are to repeat until the depth from the base of wall to exsisting ground is less than the wall height (i.e. <5'). When that condition is met I want to slope to EG at 2:1. The wall is to be in cut only, Any portions that are in fill will daylight to EG at 2:1.

 

These are initial parameters based on a preliminary assesment of the site conditions by the architect (see attached sketch). Accordingly I want to be able to adjust all the parameters should the intitial parameters do not give a satisfactory solution. Also I will need to determine the square footage of the resulting face of the walls to provide a cost estimate to the client.

 

Here are the solutions I've tried along with the pros and cons

 

1. Corridor using a benched daylight subassembly

Pros: Assmblies can Intelligently determine whether to add a bench and tier based on depth of cut

Con's: Benches overlap at concave angle points along the wall (see screen capture). Adding fillets at the angle points is not an option.

 

2. Gradings

Pros: Benches automatically clean up where they over lap vs. corridor.

By using locked criteria I can chenge the entire wall by adjusting the locked grading criteria parameters

Cons: gradings lack intelligence to automate benching and daylighting. It becomes a manual process to adjustthe benching and daylighting when the critieria changes. Also gradings cannot miter corners of thebenches.

 

I've also considered creating offset alignments for each tier and applying the wall assembly to each bench independently but the downside is I would need to create a profile for each bench and I would have to manually adjust the regions for each bench on each tier.

 

So I'll throw this one out there for the gurus who like a challenge.

 

In the attached zipped file

EG.XML = existing terrain

Base C3D.dwg=Wall corridor (2012 format)

wall.jpg=Architects wall sketch

screenhunter=corridor bench overlap

Neil Wilson (a.k.a. neilw)
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BrianHailey
Posts: 2,784
Registered: ‎04-27-2005
Message 7 of 44 (865 Views)

Re: Tiered wall assembly

04-09-2012 08:21 PM in reply to: Neilw

I haven't looked at the files but I think I may have a solution for you. It consists of a corridor with several baselines. You mentioned you could create alignments for each level of the wall but that would mean you would have to create profiles for each one, which is true however, you don't have to MANUALLY create the profiles. Create a corridor that steps back from the centerline or first level of the wall (or wherever) and have it create a surface. Use this surface with the next wall alignment and create a surface profile. Use the surface profile in the next baseline of the corridor and continue until you get to the top. You could use a set of conditional subassemblies to test if you are still in cut from the existing ground, if you are put in the wall, if not, grade back to existing ground.

 

Hope this helps.

Brian Hailey
CAD-1.com
My Blog
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Neilw
Posts: 2,251
Registered: ‎09-04-2006
Message 8 of 44 (859 Views)

Re: Tiered wall assembly

04-09-2012 10:04 PM in reply to: BrianHailey

I did consider that idea Brian. The problem is the benches cross over each other when I use a corridor, so the same problem will also appear in the profiles of the benches.

 

I've been thinking about a hybrid approach by using gradings for the benches since they clean up the overlaps, but I figured with gradings I would lose the intelligence of the subassembly to determine where to apply the benches. However an idea just came to mind of using a conditional assembly to apply the first tier of the wall if the assembly is in cut and extract the resulting featureline to use for grading the benches. I would not apply a bench at all with the assembly. The one concern I have in that scenario is the top of wall featurlelines will apppear and disappear when I adjust the wall parameters resulting in corrupt gradings.

 

Actually I now recall why I figured that approach won't work. The reason being the corridor would drop to elevation zero wherever the baseline extends beyond the ends of the surface profile. It would be a manual process to adjust the regions for each tier.

Neil Wilson (a.k.a. neilw)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
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sboon
Posts: 2,109
Registered: ‎11-08-2005
Message 9 of 44 (846 Views)

Re: Tiered wall assembly

04-09-2012 11:36 PM in reply to: Neilw

My version uses a series of featurelines built using the Stepped Offset command, with a grading object surrounding the top level to tie into EG.  The problem I had was at the ends of your alignment, where the walls are either higher or lower than EG.  On one end I tried to run a slope at 1:1 up to ground.  On the other end I extended the feature lines until they intersected with a contour line.

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907Trekker
Posts: 56
Registered: ‎10-28-2009
Message 10 of 44 (842 Views)

Re: Tiered wall assembly

04-10-2012 12:08 AM in reply to: Neilw

I love trying to model stuff like this.  In this case I think it is possible but maybe not that easy and probably a little time consuming.  Also I don't have c3d on this computer so I could only look at your pictures. This shouldn't be very hard if you are familiar with subassembly composer. 

 

I think to solve this problem without using gradings you need to be able to define the breakline that you are essentially crossing in the overlap areas.  It is the line where the two 2% grades will meet, the "V" line...This line should bisect the angle between your walls.  For the assembly, first you need to figure the cut / fill part then go into subassembly composer and make an assembly, it will have several conditions, a surface target (o.g.), and an offset target ("V" lines). 

 

First it looks to see if it is 5' or more below the grade.  If it is than start the wall, else 2:1 to og and exit.

 

Assuming you are doing the wall, first draw the top part of the wall. 

 

Calc. the distance to the "V" line (aux. point), if it is less than 10 feet, do a 2% slope to the line and exit. <- This prevents you from overlapping.  Else, do a 2% slope for 10 feet. This point should be the last point that is showing in layout mode before you save the assembly.

 

Now just copy and paste a few of those into your assembly similar to what Peter said (because you can't loop) and I think you will get the result you are looking for.  You should be able to just select all of the "V" lines when you set the target and tell it to use nearest.

 

If you haven't used subassembly composer before, take this opportunity to try it.  This isn't really a hard one to make.  Subassembly composer opens up a whole new world of possibilities.

 

There will be a small area where this won't work, it is where the thickness of the wall crosses over the "V" line.  You could modify the code to account for this.  Also if you have an area where the 2:1 cut merges into a 2% cut between walls that will probably require grading.  Dang architects...

 

Anyway, that is my initial thought.  I hope it helps you.  I usually change my mind once or twice while making a model.

 

- Mark

 

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