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Tiered wall assembly

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Message 1 of 44
Neilw_05
2277 Views, 43 Replies

Tiered wall assembly

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)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
43 REPLIES 43
Message 21 of 44
jeff_rivers
in reply to: Neilw_05

What kind of wall is it, Neil, and how will the corners be constructed in the field?


Jeffrey Rivers
Win 10 Pro 64-bit, Intel i9 3.7GHz, 64 GB
NVIDIA RTX A4000
C3D 2020 V13.2.89.0
Message 22 of 44
Neilw_05
in reply to: jeff_rivers

I'm not sure if it is a poured wall or a cmu block wall at this time Jeff, but one or the other.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 23 of 44
jeff_rivers
in reply to: jeff_rivers

I've had good success modeling walls by making one pass with a simple assembly using links (width & slope) to find the top or the toe, then creating an alignment and profile along that top (or toe) and using them as targets for a more complex wall assembly. 

 

It's true as you noted that you must manually adjust the profile (or profiles, in your case) to accurately model the tops of the benches, but it will give you fine control to determine where to end each bench. 

 

The profile also will yield the total square footage of the wall.  You can model the embedment the same way, and then get excavation quantities (I had to account for wall ex separately from the roadway ex). 

 

In my case it was a block wall, so I had my final top-of-wall profiles step up and down to follow each course as the wall grew taller.  I adjusted the profiles manually up-or-down one block height to get nice daylights that stayed within RW.  The final corridor daylighted nicely, and the actual wall, when built, matched the design very well.

 

The one problem spot was the angle point.  For the most part all the walls followed a fairly straight line except one, which had an angle point.  In the field, they constructed a closure pour to fill in the gap.  Will that be true in your case?  If so, perhaps you do not need to model exactly what's going on at the angle points.  Create your proposed profiles for the bench tops, adjust them to daylight at reasonable distances, and, extract your cut lines.

 

 


Jeffrey Rivers
Win 10 Pro 64-bit, Intel i9 3.7GHz, 64 GB
NVIDIA RTX A4000
C3D 2020 V13.2.89.0
Message 24 of 44
BrianHailey
in reply to: Neilw_05

If you know the ins and outs of the software, it's not that hard to do. Adjusted your corridor over about 20 minutes.

 

http://screencast.com/t/k8Q2R6gE0VHX

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 25 of 44
Neilw_05
in reply to: BrianHailey

It looks good Brian. What is the secret?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 26 of 44
BrianHailey
in reply to: Neilw_05

First of all, miniture curves on the alignment (edit alignment geometry). Second, multiple regions with different sampling increments (inside curves have no automatic sampled lines). Third, add manual sections where they need to have additional control (frequency, add manual stations). Fourth, edit the sections manually at the angle points so they continue to have one angle point (section editor).

Brian J. Hailey, P.E.



GEI Consultants
My Civil 3D Blog

Message 27 of 44
907Trekker
in reply to: BrianHailey

I was thinking about that, but did you adjust the grade of the two inside lines to something other than 2% so there isn't a bump in the grade?  The new grade would depend on the angle so each would need to be calculated.  Also it would cause issues if you wanted more sample lines. See attached.

 

I'm not sure if we are trying to achieve that level of accuracy though.

Message 28 of 44
Neilw_05
in reply to: 907Trekker

It looks like you guys are closing in with the fillets. When you get the bugs worked out can you post the design file for evaluation?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 29 of 44
907Trekker
in reply to: Neilw_05

Neil,

 

Any chance that you could upload the existing grade, or at least a portion of it in this area?   Possibly export it to a land xml. 

 

Thanks,
Mark

 

 

 

 

Message 30 of 44
907Trekker
in reply to: Neilw_05

Nevermind, I'm sorry.. I see it now.

Message 31 of 44
Neilw_05
in reply to: 907Trekker

One way to deal with the bench overlaps is to project them out at 0%. Then the overlaps don't matter and we can use them to a create reference surface for the next tier. Each tier could then be a separate alignment. By sampling the reference surface from the projections we can establish the profile for the next tier and then apply a 0.2' vertical offset from the profile to establish the bottom elevation for the tier (0.2/10=2%).

 

With this approach we can extract featurelines from the bottom and tops of the tiers and let the TIN handle the corners. There is still the problem of the truncated corners at the convex angle points, but if we project the benches far enough we can ensure a surface for the next tier. The one thing I'm not sure about is how to handle the portions of the tiers that do not have a reference surface from the previous teir.

 

Can this work?

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 32 of 44
Neilw_05
in reply to: Neilw_05

I realize now that the zero % slope idea won't fly if the top of wall is not level so I'm back to the drawing board.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 33 of 44
907Trekker
in reply to: Neilw_05

Just wanted to let you know that I'm pretty close to having my idea done.  It is drawing walls and checking a bunch of stuff.  No overlaps, it did turn out to be a bit more complicated than I thought regarding checking conditions.  For example, when I get to the back of a wall I am looking out 10 feet at the 2% grade and then checking if there is enough vert height for the next wall, if not I am just doing a 2:1 from that point.  Otherwise you could have a scenario where you go 10', get to the next spot and then go 2:1.  I ran it this morning and found one bug, as soon as I get that fixed I'll send it your way.   I'm working on it in the evenings so it probably won't be until tomorrow, just learned I have to do a topo at low tide today and that is at 6 pm..

 

Sorry for the delay,

Mark

Message 34 of 44
Neilw_05
in reply to: 907Trekker

Thanks for looking at this Mark. I'm looking forward to seeing a solution.

 

I have come to realize I need to correct one of the citeria. If the depth between the base of wall and EG is less than 5' we still need to add a wall. Otherwise the 2:1 slope will chase the EG slope well up the hill. So I'll need to add tiers until the walls go into a fill condition.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 35 of 44
sboon
in reply to: Neilw_05

I think that you will want to set a minimum height Neil.  Otherwise you could find yourself dealing with 6" high segments in short sections along the top tier.

Steve
Expert Elite Alumnus
Message 36 of 44
Neilw_05
in reply to: sboon

You are right Steve. I think we'll need to require a min 3' high wall with 1' min, 2' max. above EG at the top. I can model a swale behind it with gradings to convey any trapped surface runoff.

 

In cases where the min/max constraints are not met, then go hopefully it will catch grade in a reasonable distance if we project at 2:1 to EG. 

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 37 of 44
Neilw_05
in reply to: Neilw_05

I think I'm really close to getting this to work. I just need somone with expertise to help me fill in the gaps.

 

Here is what I've come up with:

 

1) Use offset alignments for each tier.

2) Create a bottom of wall profile for the first tier.

3) Create a feature line from the profile of the bottom wall

4) Create a stepped offset featureline from the bottom of wall feature line at a slope to correspond with the slope between the bottom of each tier. In this example the slope will be 52% (5' +10'x2%)/10'. Make sure the offset FL is beyond all the tiers so we can make a surface to use as profiles for the tiers. I found I needed to add featurelines that span the tiers across the angle points to get a nicely mitered surface.

5) Create a surface from the featurelines and sample it for all the tier alignments

6) Create an assembly with conditional branches to add a 5' vertical tier when in cut and no tier in fill

7) Create a corridor and add all the baselines and apply the assembly

 

I am able to get the corridor to build the bottoms and tops of the tiers but I don't know how to make it fill the gaps along a tier when it transitions from cut to fill. I'm sure it is an easy fix so I'm hoping one of you will have the answer. Once I get the corridor to generate all the featurelines I think we can build a surface from them.

 

To change the parameters of the walls we would change the slope of the reference surface by adjusting the slope between the bottom and top reference surface featurlines and/or adjust the horizontal offsets of the tiers. To aid in determining what the ideal slope will be we can create a grading from the bottom of the first tier that targets EG and tweak the slopes until we get a good fit.

 

If this works it will be a very simple solution and it doesn't require fillets on the baselines.

 

I am attaching my design file for reference.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 38 of 44
907Trekker
in reply to: Neilw_05

Here is mine.  It isn't working as good as I hoped but it does calculate the wall toes and tops plus daylights and will not overlap.  It looks funny when it goes from a wall section to a cut section (because there is less than 3 vert feet to eg.)  Another thing that really bugs me is that you can't do a corridor shrinkwrap with it, not sure why.

 

Anyway, here is the procedure to use it.

1. load the subassembly

2. stack a few of them back to back (see the pic.)

3. put some small curves in your alignment for outside angles (I used 0.02' R)

4. put in the "v" breaklines for the inside angles

5. build the corridor and target the ground, and your lines.

 

Then you can mess around with it as much as you want, it will update. But unfortunatly, in the end you will have to do some custom grading.

 

You'll see that it is still a work in progress, there is a feature line that is connecting that shouldn't. Open up the pkt file with subassembly composer and look around, pretty much everything has comments.  I'm sure somebody could it it in 1/2 the steps, but hey, I had a fun time messing with it.  I'll probably mess around with it this weekend.  Let me know if it is handling something completely wrong and i'll make the change.  I see that I have more benches than you but when I check the cross sections they appear to be correct.

 

The capture 3 image shows all of the variables you can change.

 

Thanks,
Mark

 

Message 39 of 44
Neilw_05
in reply to: 907Trekker

I've taken a few minutes to work with your assembly Mark.

 

I'm still having problems with overlaps on the benches. I've added small fillets to my baseline and tried adding sections to the mid points of the fillets but I can't get rid of the overlaps or get mitered corners. I don't understand your guidance to "...put in the "v" breaklines" and "target..your lines". Could you clarify?

 

I've put my approach aside until I figure out how to get the corridor to build a surface from the feature lines. So far I haven't been able to make it model the faces of the tiers.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 40 of 44
charlie445
in reply to: Neilw_05

Cheers for all the solutions, ill try to figure out now..

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