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Sub assembly - variable earthwork slopes beyond alignments

13 REPLIES 13
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Message 1 of 14
Rossm90
5894 Views, 13 Replies

Sub assembly - variable earthwork slopes beyond alignments

Hello Everyone,

 

I just want to start by saying I have been extremely impressed with the speed and effectiveness of finding Civil 3D solutions through this forum. However I do not think there is a way to solve the problem below without making a custom sub assembly.

 

There is a common problem that I run into when modelling earthworks on airfields. All Taxiways and Runways will have sepirate areas that determine the slope of earthworks in that area. As an example I will explain my problem for a Runway.

 

Any ruwnay will have a Strip area (150m offset from its centreline) and a Clear and Graded area (105m offset from its centreline). Therefore any earthwork slopes between the runway pavement edge and 105m offset from the centreline will be determined by the requirements within the Clear and Graded Area. Likewise any earthwork slopes between 105m and 150m offsets from the centreline will be determined by the requirements of the Strip area.

 

My problem is that when overlaying a runway, the new earthworks required may extend beyond the clear and graded area (and into the strip) at some points but not in others.

 

Therefore I would like a sub assembly that does earthworks at a set slope unless it passes the clear and graded line where it would then continue the earthworks using a different slope. It should be pointed out that the clear and graded line will be present along the entire length of the runway and the earthworks may or may not extend beyond it.

 

Just for the sake of clarity, when I say earthworks, I mean the subassembly within autocad that will "Cut or Fill" at a set slope until it reaches a chosen surface level. Similarly the "clear and graded line" and "strip line" are 2D and mearly delineate the areas in plan.

____________________________________________________________________________________________________

 

So that is my problem and a solution to it would help me save time and make my model more dynamic. As it stands I have been getting around this problem by modelling the earthworks at the initial slope (clear and graded area) and then manually amending the corridor to use a different assembly where the earthworks extend beyond the clear and graded line.

 

Thank you in advance for any time and consideration you spend on helping me out with this problem and I look forward to hearing about any solutions that you have!

 

Many thanks and Good Luck!

 

Ross

 

13 REPLIES 13
Message 2 of 14
fcernst
in reply to: Rossm90

Provide a good clear sketch for the problem.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 3 of 14
Rossm90
in reply to: fcernst

Please see attached for the sketch of the situation.

 

 

Message 4 of 14
fcernst
in reply to: Rossm90

You could use conditional Cut/Fill assemblies to test whether you would be at a cut or fill at the Clear and Graded offset, at the 1% projection.

 

Then have the two subassembly scenarios branches to choose from, straight 1% daylight if in cut at the test point, or the 1% with the 2% break if in fill at the test point.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 5 of 14
Rossm90
in reply to: fcernst

Would the conditional cut/fill sub assembly still register the situation as Cut if the earthworks tie in before the test point? In theory there would be no cut or fill at that point because the earthworks tie in before it reaches there.
Message 6 of 14
Rossm90
in reply to: Rossm90

Also, the situation in the sketch I showed is in fill, however it is possible that the situation would require the eathworks to cut into the E.G. to tie in along the same runway. Would your solution function in both situations or would I need sepirate assemblies?
Message 7 of 14
fcernst
in reply to: Rossm90

In theory there would be no cut or fill at that point because the earthworks tie in before it reaches there.

 

You are executing a 1% projection all the way out to the Clear and Graded offset,  and testing if that is above or below ground.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 8 of 14
Rossm90
in reply to: fcernst

Apologies for the lack of clarity in my sketch.

Section A-A is to show the earthworks projecting out at 1% until it reaches the existing ground which in this case happens to be before the clear and graded offest.

Section B-B is to be the situation when that 1% projection takes the earthworks upto and beyond the clear and graded offset.

Message 9 of 14
fcernst
in reply to: Rossm90

Apologies for the lack of clarity in my sketch.

 


None needed. It very clearly poses the problem.

 

 



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 10 of 14
fcernst
in reply to: Rossm90

Would your solution function in both situations or would I need sepirate assemblies?

 


You would need to apply the opposite logic to the 1% projection test at the Clear and Grade offset.

 

You still need only one assembly. you would add a Conditonal, upstream, at the end of the Overlay for proper branching.

 

 



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 11 of 14
Rossm90
in reply to: fcernst

That makes sense, but how would the assembly behave if the earthworks tied in before the Clear and Graded as shown in the sketch?
Message 12 of 14
fcernst
in reply to: Rossm90

It would tie in at 1% (if you want 1% in cut also), and you would have cut material as defined for the area below EG and above FG.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 13 of 14
Rossm90
in reply to: fcernst

I am very sorry, but I am about to head out for the weekend (I am in England thus the time difference!).

I want to thank you for the time you have spent (did a bit of snooping and realised you set up your own engineering company)
However, if you are still up for helping me with this issue I will probably bring it back up on Monday.

Many thanks and have a good weekend
Message 14 of 14
fcernst
in reply to: Rossm90

Yes, if you are also possibly considering subcontracting with Ernst, I would definitely be interested in this work.



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com

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