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Challenging Grading Project

27 REPLIES 27
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Message 1 of 28
randcdavidson
679 Views, 27 Replies

Challenging Grading Project

I've been assigned to do this grading project and it is becoming a challenge at least for me at this point. What is needed is top of Pond set to OG elevations, down 3.5:1 to a relative elevation of 5' then bottom infill. So far so good.

Now they want the bottom to funnel into a drainage inlet which is set at 368.55. Then they want the remainder of the pond bottom to all slope towards this inlet at about 0.5%.

 

SO what I figure I'll do is grade down the top the 3.5:1 at 5 feet deep. Explode the grading and take the bottom feature line and insert a low point near the drain inlet at el 368.55. Then I'll use the set grade/slope between points command and slope this featureline out at 0.5 percent to the extreme corners of the pond. Once that is set I'll do an infill and create a surface I'll call "bottom". Next I'll re-grade the top down the 3.5:1 only this time I'll target the bottom surface then do an infill to get one single grading.

 

Sound like a good way to tackle this? Before you answer take a look at the attached image and see what kind of animal I'm up against. Smiley Surprised

27 REPLIES 27
Message 2 of 28
Joe-Bouza
in reply to: randcdavidson

That image makse me wonder how you have .5% in any given leg at the same time as you described? Is OG more or less 0.5% across the basin to the the inlet location?
Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 3 of 28

No. OG is fairly flat and if anything drops off lower from the inlet at about 0.2%

Message 4 of 28
Joe-Bouza
in reply to: randcdavidson

So your goal is the slope at .5% across the basin (all points) or only in the vacinity of the inlet? for what distance?
Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 5 of 28

Yes I need to slope the entire spiderweb of a basin about 0.5% down so that all the water will drain to the discharge at elevation 368.55. Now it does not have to be exactly .5% I kind of figured I'd work out from the discharge a half percent north and south on the first (nearest) legs then continue on the remaining three legs.

Message 6 of 28
Neilw_05
in reply to: randcdavidson

Given that geometry I'd create some flowlines down the middle of each finger, all sloping from the outlet at 5%. Then I would apply gradings to the flowlines outward at some slope to make a nice pan for the fingers and make a target surface for the sides of the pond. 

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 7 of 28
Joe-Bouza
in reply to: Neilw_05

Thanks Neil
thats where I was heading. I was not convinced the fingers were getting any flow based on the original description. The OP should be weel on their way now.
Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People)

HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

64 Bit Win10 OS
Message 8 of 28
Neilw_05
in reply to: Joe-Bouza

Thanks for the feedback Joe.

 

Thinking about it a bit more I realized that it would be better to not apply any gradings to the flowlines at all. Instead just grade from the top of the pond down to the relative elevation target and add the flowlines and infills for the bottom. That way all the parameters are met. Of course this will result in variable slopes between the bottom edges of the pond and the flowlines. The flowlines can be tweaked to compensate for excessive slopes.

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 9 of 28
cwitzel
in reply to: randcdavidson

For ponds I almost always use a dummy surface graded in all directions towards the outfall.  In other words I set an elevation at my outfall and have a grading object that goes in all directions at the desired grade.

 

I then grade down to this surface with my pond top.

 

When we have a trickle channel say at point .5%, I will run a feature along the bottom then grade away from it at 2% well past extents of the pond.

 

Hope that helps.

 

Thanks,

Conan Witzel

Thanks,
Conan Witzel
Civil 3d 2021 SP1.1
Smoking BOXX Apex 2 Workstation
Message 10 of 28
randcdavidson
in reply to: cwitzel

Conan. I ike that idea. Now how can I grade in all directions as you state. Have you seen my attached image and what I'm being asked to create?

Message 11 of 28
randcdavidson
in reply to: Neilw_05

Neil when you say "add the flowlines" Do you mean add featurelines and re-grade them in the infill? I'm asking because all the ponds I have done to date have been simple rectangular with flat bottoms.

Message 12 of 28
Neilw_05
in reply to: randcdavidson

Yes, If you use featurelines and have them in the same site they will automatically influence the grading infill and you should see the contours adjust to the flowlines as you change their slopes or elevations. Don't extend the flowlines to touch the bottom of the pond edge or it will create closed areas. Leave a good sized gap from the ends and one infill should cover the entire pond bottom and you'll have a nice pan all around the ends of the flowlines..

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 13 of 28
Neilw_05
in reply to: Neilw_05

Here is a file for you to look at (2013 format)

Also a DWF for those who can't open the file. Rename Pond Model.dwg to .dwfx

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 14 of 28
cwitzel
in reply to: randcdavidson

Writing from my iPhone, so I can't see. Since a circle can't be a feature line, I trim a circle very tight to make an arc, convert it to polyline and make it a feature line with the elevation of the desired outflow. Make or use a grading that is my desired slope to the outfall. Put it in a surface (or auotmatic even better). And grade to the surface created.

The arc is tiny to start but the grading is large enough to cover the pond.

Hope I am clear from home. If not I will try from work.

Sent from my iPhone
Thanks,
Conan Witzel
Civil 3d 2021 SP1.1
Smoking BOXX Apex 2 Workstation
Message 15 of 28
randcdavidson
in reply to: cwitzel

Cwitzel. I see. Also yes a circle can be a featureline. Run mapclean and go to cleanup methods and select "circle to polyline" then convert that new polyline into a featureline and there you have it.

Thanks

Message 16 of 28
Neilw_05
in reply to: randcdavidson

I didn't know about that function in MapClean. One Kudo for you!

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 17 of 28
cwitzel
in reply to: randcdavidson

Yep!  Same here.  Did not know that one!  

I will do that once and keep it in a block on tool palette.

 

Thanks,

Conan Witzel

Thanks,
Conan Witzel
Civil 3d 2021 SP1.1
Smoking BOXX Apex 2 Workstation
Message 18 of 28

Ok new problem. I did the graded pond bottom as directed but now as I go to grade the top rim down to the new surface it is not an available surface in my create grading tools set the target surface. Everything is in the same site. My pond bottom surface was created from the grading group.

I'm thinking I have some site issues as I have about a half dozen sites I'm dealing with.

Message 19 of 28
troma
in reply to: randcdavidson

Did you actually create a pond bottom surface, or just the grading? You might be better off to do the side slope grading in a different site.

And, as always with gradings, save often, audit often. And save every time before you audit. I'd hate to see the whole thing explode in your face...

Mark Green

Working on Civil 3D in Canada

Message 20 of 28
cwitzel
in reply to: randcdavidson

I usually have the pond bottom on its own site.  You don't want it to interact with the other feature lines.

Thanks,
Conan Witzel
Civil 3d 2021 SP1.1
Smoking BOXX Apex 2 Workstation

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