AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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randcdavidson
Posts: 223
Registered: ‎06-07-2010
Message 1 of 28 (374 Views)

Challenging Grading Project

374 Views, 27 Replies
10-07-2013 12:14 PM

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. :smileysurprised:

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Joe-Bouza
Posts: 4,884
Registered: ‎12-15-2008
Message 2 of 28 (346 Views)

Re: Challenging Grading Project

10-07-2013 01:29 PM 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) Civil 3D 2012 & 2013
HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


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

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randcdavidson
Posts: 223
Registered: ‎06-07-2010
Message 3 of 28 (339 Views)

Re: Challenging Grading Project

10-07-2013 01:39 PM in reply to: randcdavidson

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

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Joe-Bouza
Posts: 4,884
Registered: ‎12-15-2008
Message 4 of 28 (314 Views)

Re: Challenging Grading Project

10-07-2013 02:32 PM 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) Civil 3D 2012 & 2013
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 Win7 OS
Mentor
randcdavidson
Posts: 223
Registered: ‎06-07-2010
Message 5 of 28 (310 Views)

Re: Challenging Grading Project

10-07-2013 02:50 PM in reply to: randcdavidson

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.

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Neilw
Posts: 2,253
Registered: ‎09-04-2006
Message 6 of 28 (284 Views)

Re: Challenging Grading Project

10-07-2013 05:08 PM 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)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
HP Pavillion h8xt, i7 2600, 12 GB
RADEON 6450, 1 GB
http://www.sec-landmgt.com
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Joe-Bouza
Posts: 4,884
Registered: ‎12-15-2008
Message 7 of 28 (250 Views)

Re: Challenging Grading Project

10-08-2013 04:12 AM in reply to: Neilw
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) Civil 3D 2012 & 2013
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 Win7 OS
*Expert Elite*
Neilw
Posts: 2,253
Registered: ‎09-04-2006
Message 8 of 28 (225 Views)

Re: Challenging Grading Project

10-08-2013 08:19 AM 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)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
HP Pavillion h8xt, i7 2600, 12 GB
RADEON 6450, 1 GB
http://www.sec-landmgt.com
Active Contributor
cwitzel
Posts: 36
Registered: ‎11-13-2006
Message 9 of 28 (192 Views)

Re: Challenging Grading Project

10-08-2013 01:03 PM 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

Mentor
randcdavidson
Posts: 223
Registered: ‎06-07-2010
Message 10 of 28 (181 Views)

Re: Challenging Grading Project

10-08-2013 01:46 PM 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?

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