Road Design - Surface to Surface

[strsi681]

Hi Everybody,

I have been given a road design DXF file. From this I've created my existing surface, design surface, alignment, profile, cross section views and this is the state my current dwg sits. 

I have been asked to compute volumes of the drains which is generally fine except for the following "rules" that need to be followed. 

1) I must subtract 0.310 from the design surface to use as the "bottom" of drain surface (can be done easily enough)

2) Thinking from a cross sectional perspective now: Where the existing surface cuts through the road batter and reaches the design cut batter - this will be used as the "top" of drain surface

3) If the existing surface doesn't cut through the road batter (i.e. the existing surface is much higher or much lower) then I will keep the grade of the road and daylight it out untill it hits the design cut batter. Essentially projecting the crossfall of the road surface untill it reaches the design batter surface. 

Also worth mentioning the road is a relatively simple - straight, right hand bend with super, then a straight i.e. the cross fall of the road isn't always going to be -3%.

These "rules" were how the job price was originally quoted so they have asked me to replicate it and come up with a volume. 

I've scratched my Civil 3d brain and am absolutely stuck. The only method I can come up with is create polygons over my cross sectional views where these parameters occur, obtain the areas and do cross sectional end volumes. Which will be relatively inaccurate and very time consuming. 

Any help would be huge guys. 

Thanks in advance,

Simon 

[mathewkol]

A sketch would help.

[strsi681]

Of course, please see attached.

Hopefully it makes sense. 

1) Volumes need to be calculated for both situations

2) X-Fall of road changes due to curve

[Jay_B]

For Situation 2, wouldn't you want the hatching (cut) to also include the entire area/volume from the existing surface down at least to the top of the Design Surface shown?

[strsi681]

Yes in theory I believe you should. The reason why I won't be however is because I need to replicate the volume that was initially quoted and the parameters mentioned is how this volume was calculated (apparently).

*the person who ran the initial volumes has since left the project

[strsi681]

As I only have design strings...

Is there a function in civil 3d where I could select the 3d centreline, select the 3d shoulder line and then project this perpendicular grade to the cut batter? That would get me started on the second situation.

[mathewkol]

If you have the polylines that represent to CL, Edge of Pavement etc, a corridor could pretty easilty created that would give you what you need.  Is that in your wheelhouse?

[strsi681]

I have 2 of the 3 parts that define a corridor. I have the CL alignment and the CL profile (defined by CL alignment along the design surface). I don't have an assembly though. So I'm not sure how to proceed from this point.

Thanks for your assistance Matt.

[mathewkol]

Do you have a dataset you can attach?

[strsi681]

Thanks for your help everyone (particularly mathewk) but I've created cross sections, manual polygons and run average end area volumes. Very time consuming but we got here.