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

13 REPLIES 13
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Message 1 of 14
bham4ever
7209 Views, 13 Replies

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

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.

"Never say Never"
13 REPLIES 13
Message 2 of 14
Jason.Ferrelli
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
Message 3 of 14
fcernst
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 2024
Ernst Engineering
www.ernstengineering.com
Message 4 of 14
Joe-Bouza
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)

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 14
fcernst
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 2024
Ernst Engineering
www.ernstengineering.com
Message 6 of 14
Joe-Bouza
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)

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 7 of 14
fcernst
in reply to: Joe-Bouza

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



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 8 of 14
john.mckenzie
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.

Message 9 of 14
fcernst
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 2024
Ernst Engineering
www.ernstengineering.com
Message 10 of 14
john.mckenzie
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.

 

Message 11 of 14
Joe-Bouza
in reply to: john.mckenzie

I would think that only applies if the the cross fall varies? If the typical section does not vary why would a 3 line be required?
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 12 of 14
fcernst
in reply to: john.mckenzie

yuck.

 

Thanks, you have me feeling a lot better about my situation now.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 13 of 14
fcernst
in reply to: Joe-Bouza

They want to see that the gutter flowline never falls below 0.5%:  around curves, widenings, approaches to sag inlets, etc.

 

 



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 14 of 14
Joe-Bouza
in reply to: fcernst

Got it
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

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