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Is there a way to model a takeoff subgrade that is a hybrid of a site plan and corridor?

Question asked by Patrick L'heureux on Jan 25, 2019
Latest reply on Jan 26, 2019 by Patrick L'heureux

Something that I have run into is that there does not seem to be a way to modify a takeoff subgrade surface besides applying MSI improvements to the finish grade surface. This works well for "sites" but the downside to this is that you will only get vertical faces, you cannot get sloped subgrades.


There are many cases where this is not correct such as the subgrade for a roadway, subgrade for building E&B, leach beds, underground detention systems, and  MSE walls. And truthfully real life applications. The typical may show a vertical face but it is pretty hard to build a vertical face in a fill. Therefore there will be waste and it should be taken into consideration. A lot of these calculations have to be performed separately. Sometimes separate calculations are necessary, but sometimes I feel it is because there is not a better way off running the calculations.


You could model the subgrade surface manually but unfortunately there is no way of replacing that with the automated surface. Maybe if there was a way to add a bound and designate an area that will deviate from the traditional vertical subgrades. This area could be composed of entities such as side slope lines, corridor components or manual modeling and allow the user to add entities to subgrade surfaces similar to how the can with the finish design surface.


I have tried to model the subgrade of a roadway and blend this into the takeoff subgrade of the rest of the site but have not found a way of doing so and have the takeoff report reflect this hybrid subgrade surface. There are ways of obtaining the values but they require multiple methods and compiling multiple reports to get results.


One work around is to:

  1. Model the corridor; finish, select layers, and subgrade
  2. Apply the subgrade surface to the finish design surface instead of the finish surface
  3. Do not apply any MSI values within the corridor bound
  4. Run the takeoff report to get the mass earthwork and selects outside of the corridor
  5. Run the corridor takeoff to get the roadway select values


Is there something that I am missing to accomplish a hybrid subgrade? If not, would it be possible to incorporate this in the future?


Ideally I would like to take the attached site, a combination of 2 roadways and some traditionally site grading, and be able to run one takeoff report to get all of my values. 


Thank you!