Trimble Business Center

I got this question the other day from our dealer in Scotland - I thought that it was worth sharing the Question and Answer for all you Takeoff People out there

Here is the Question

Originally I thought the question was about Overex, it was then clarified as follows which was an entirely different issue to address (so that is the background)

Hi Alan,

So I can’t seem to get this command to work when the areas are in fill. Obviously I understand that this command has been designed to over excavate the ground rather than to build on soft ground conditions. What we are doing here is to have certain areas on the site that we say that we cannot just use the clay that was removed from the cut areas on site.

This is a very frequent stipulation in the UK where the client says that any made-up ground under anything like driveways, roads and houses needs to be granular material (often Capping or Type 1 aggregate) whereas any areas of fill (e.g. under footpaths, gardens etc) can just be clay.

As you can see below with a cross section through the attached site I have crudely hatched areas of fill under roads and houses that would need to be granular material rather than clay from the cut areas.

I can get this to work on a corridor but generally we are finding that as this is done at the estimating stage of the project it is preferable to use an area based method using the take-off module.

I attach a project that has foundations and roads in fill. Can you please point in me in the right direction?

I appreciate you are just back from leave so I realize I may have to wait a wee while.

Very many thanks again.

Here was the answer provided - hope this helps people with similar questions - this is a global need not just a Scotland need

OK - so the way to do what you want right now is to use Areas of Interest for each of the object fill Areas where you need to use Granular Fill vs normal fill. You can do this with one AOI (multiple boundary lines) or multiple AOIs (each a sngle boundary) - then your report for Cuts and Fills will be broken into AOI Areas and "Other Areas" provided you check the check box in the Report generator - then your Fills reported by AOI will be your Granular Fill Quantities and the Other Areas will be use any material including the Clay.

The Green Line is my Original Ground at Elevation 100

The red Lines are Building Pads at varying Elevations - the Tall Thin one on the Right Side has elevations on a slope from 98 to 102, the others are at 109, 108, 107 respectively. The Blue Line is some other FG Line at Elevation 107. The Big Pad is at 110. So all are either 10% in Fill or split Cut to fill. I have applied ite Improvements to adjust the Subgrade at each pad only to give me a subgrade adjusted surface. Here are some sectional views to visualize what I have done here.

SO I now create an AOI called Granular Fill and use the 5 Pad Boundaries for that single AOI. I could use the Blue Line plus the 5 Pads as a second AOI called Any Fill. If you define Boundaries inside Boundaries they become holes in the calculation The "Include Other Areas" check box effectively does this for all other areas of the Design Surface - sometimes it is better to control your destiny and you get to name that AOI "Any Fill"

When I report the Quantities now in my Earthworks section I will get this

I think this is what you want - as a check - if I report the Tall Thin Building which has some Cut and Some Granular Fill separately this is what I get (I am now double counting the Tall Thin Building as I count it in both Granular Fill and the Building 5 AOIs. I would have to exclude it from the Granular Fill AOI to separate it entirely - then I would report each area as a separate AOI.

If you get a scenario where you have to apply Granular Fill but only to a certain depth below subgrade when in fill then that would be a different beast - but since you have to apply Granular Fill for full depth this process works just fine - you just have to create your Areas of Interest boundaries (which is typically not hard because they are typically beneath defined structural areas like Buildings or Road Pavement etc.. Careful naming of the AOIs helps the readability of the reports - so use e.g. Building 5 (Granular Fill) or Areas - Granular Fill, Areas - Normal Fill etc. and then your reports read nicely and are very clear for the reader. 

Alan