AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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bham4ever
Posts: 35
Registered: ‎01-08-2009
Message 1 of 14 (6,838 Views)

Roadway design on profiles for low points in a Sag for drainage structures

6838 Views, 13 Replies
08-23-2013 07:37 AM

Is there a way to design the road profile to use the low point at a certain Roadway station so you can put your storm inlets to line up with property lines. Because when you create a Sag the PVI is not where your low point falls on the profile. It would be nice to be able to drag the low point not the PVI to create the low point where you need it instead of a sort of back and forth dragging the PVI of the vertical curve.

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Jason.Ferrelli
Posts: 79
Registered: ‎08-08-2008
Message 2 of 14 (6,774 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

08-29-2013 11:55 AM in reply to: bham4ever

One thing I have used in the past to manipulate the low point without using the the profile grips has been the profile layout parameters. This will allow you to modify the properties of a PVI to shift the low point as desired.
To get to this tool:

 

  1. Click on the profile you wish to modify
  2. Right mouse click and select Edit Profile Geometry
  3. This will open the profile layout toolbar. In this toolbar these is a button when hovered over says "Select PVI". Click that button and select the PVI assosicated with your low point.
  4. This will open the Profile Layout Parameters and allow you to manipulates the properties.

These is also been simalar posts regarding this topic located here.

http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Vertical-curve-through-known-low-point/td-p/3082980

 

I hope one of these methods will help you get the desired results.



Jason Ferrelli
Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 3 of 14 (6,740 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-04-2013 05:18 AM in reply to: bham4ever

On the gutter flowline design to a Sag Inlet, do you guys have to provide 0.5% tangents on the gutter flowline coming into and out of the Low Point, so you don't get appx 40-50 feet or so of too flat of flowline (<0.5%) ?

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
*Expert Elite*
Joe-Bouza
Posts: 4,966
Registered: ‎12-15-2008
Message 4 of 14 (6,730 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-04-2013 05:51 AM in reply to: bham4ever

The parabolic curve and lp/hp are a function of the grade in grade out and curve length, the lp/hp can be targeted mathematically but this would also be a trial and error approach. Considering Fred's advice a minimum k value of 20 is required. There are many factors to consider in designing the sag. If these parameters are not of concern Jason's advice via trial and error will get you there. Adding to Jason's post set the editor to entity and pick the vc then you can play with the values. I played with the length and in 3 or 4 tries got my lp station where I wanted it

I would like to ask your question slightly differently: Where is the vertical curve calculator?

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
Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 5 of 14 (6,713 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-04-2013 03:04 PM in reply to: Joe-Bouza

Considering Fred's advice a minimum k value of 20 is required.

 


No, we're just not allowed to put vertical curves on the Sag gutter flowlines here.

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
*Expert Elite*
Joe-Bouza
Posts: 4,966
Registered: ‎12-15-2008
Message 6 of 14 (6,702 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-05-2013 05:10 AM in reply to: bham4ever

I was only thinking K=20 gives 0.5% 20 feet from the lp, no?

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
Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 7 of 14 (6,690 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-05-2013 07:25 AM in reply to: Joe-Bouza

Right, for 10 feet either side of the LP it's flatter than 0.5%.

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
Mentor
john.mckenzie
Posts: 222
Registered: ‎12-19-2006
Message 8 of 14 (6,677 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-05-2013 09:41 AM in reply to: fcernst

Fred,

 

Are you then required to provide gutterline profiles that are independent of centerline and typical section in order to avoid sag vertical curves at the flowline?

 

I have seen gutter line profiles on production dwgs for intersections but I cannot remember seeing them on any dwgs for mainline/ non-intersection flowlines.

 

Or do you manage this with a typical detail for the basin inlet, and let the actual model reflect otherwise approaching the inlets.

 

I have seen that type of detail provided.

 

if you are accurately modeling the inlets AND areas approaching them I would be curious to know your workflow/methodology.

Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 9 of 14 (6,668 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-05-2013 11:20 AM in reply to: john.mckenzie

Yes, we are within one of those 3-profile jurisdictions with separate gutter flowline stationing and profiling. 

 

Workflow: Tracing....praying, living a good life, in the vain hope things don't change...

 

I have made a SAC subassembly that can drive the lane cross slope from the gutter flowline profile. Helps a little bit to model Sag inlets.

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
Mentor
john.mckenzie
Posts: 222
Registered: ‎12-19-2006
Message 10 of 14 (6,663 Views)

Re: Roadway design on profiles for low points in a Sag for drainage structures

09-05-2013 11:23 AM in reply to: fcernst

yuck.

 

my workflow includes living the good life too but I must be doing something wrong. It is not providing nearly the level of success it seems to provide others.

 

 

Oh well.

 

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