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Multiple subgrade surfaces

  • 1.  Multiple subgrade surfaces

    Posted 10-28-2020 05:40
      |   view attached

    I think this is a simple question but I wanted to see if there was a better workflow process for subgrade data prep.  We mainly perform earthwork/utilities on smaller commercial sites.  At the time of bid, I would say that the majority of projects we work with do not offer the design cad files for bidding purposes, so most of the time I am importing vector pdf information and then performing a lot of cleanup.


    Many of these sites have multiple paving subgrades (LD, HD etc.) that abut each other.  So the finish grade is easy enough to enter, but because TBC will not allow true vertical line segments to share the same horizontal space, I am forced to create a lot of additional minor offsets and breaklines.  I usually enter closed lines for edge of pavement, light duty, edge of pavement HD, top back of curb, edge of sidewalk and so forth.  And then I have to go back and make sure all their finish grade VPIs match up exactly at every point.


    I was just curious if this was the best way to perform subgrade adjustments like this or if there is some type of macro that would speed up these offsets.


    [4] C100 SITE PLAN.pdf   1.09 MB 1 version

  • 2.  Re: Multiple subgrade surfaces

    Posted 10-28-2020 15:36

    How about Site Improvements?


    Add closed breaklines with "Sharp and Texture Boundary" type to the Finished Surface.

    Define Materials and Site Improvements for every Pavement Type.

    Click (apply) each Pavement Type to each boundary.

    Now you can generate as many subgrade surfaces as you need, for each material layer if you choose.

  • 3.  Re: Multiple subgrade surfaces

    Posted 10-29-2020 08:13

    Thanks Marian for your reply!  The two issues I run into with that are:

    -Unlike AutoCad, it doesn't seem like TBC allows you to share a common horizontal space with another subgrade.  So if I have say a HD pavement section adjacent to a LD pavement section, I have to create a small offset with a completely separate closed line.  Otherwise I get an error flag stating that "this region has been assigned multiple conflicting area-based site improvements."


    -The other issue is I usually elevate my subgrade boundary lines to add to the finish design surface.  And so if I have subgrades that share a boundary vertex - for instance, on interior curb lines, where HD paving and LD paving would meet - I have to constantly review all of those sloping lines to make sure their finish elevations match.  Should I be creating separate layers/linework for the vertical information?  


    I apologize if these questions seem simple, I'm just coming over from a different system and seeing what the best process would be for our specific needs.  

  • 4.  Re: Multiple subgrade surfaces

    Posted 10-29-2020 13:50

    I do not have elevation on my boundary lines. I will copy my edge of pavement and whatever I need for the subgrade adjustment using track region outline but make it "?" for the elevation. It keeps thing from getting messed up if you change the elevation of the edge of pavement.

  • 5.  Re: Multiple subgrade surfaces

    Posted 10-30-2020 05:26

    Thanks Tom! I had been used to elevating each subgrade boundary.  But like you said if you have to make an elevation adjustment on one, then I'm forced to make adjustments on all bounded lines that border it.  I'll give that a shot by copying/creating a separate layer that will be used strictly for TIN creation to represent final grade unbiased of any subgrade, and then not using any of the EOP in the surface design.  

  • 6.  Re: Multiple subgrade surfaces

    Posted 10-29-2020 15:04

    Create your finished design, then apply site improvements and when you build surfaces it builds a subgrade surface. I use this all the time to make grading models at subgrade with varying pavement thicknesses all over the place.


    You don't need to have closed lines around every site improvement, use the Categorize command in the takeoff tab, select the design tab, and make sure the layers that will contain edge of pavement or changes in thickness have the 'Contains potential boundary lines' box checked. Once you have the layers set up use Identify Site Regions to apply improvements you created from MSI Manager. When you press Build Surfaces the subgrade model is created.


    You can also build subgrade models using the Create Subgrade command under the surfaces tab. I use this to build grading models for specific areas. If we're going to put in limestone below future concrete paving I can create a model at the top of stone with a few clicks.   

  • 7.  Re: Multiple subgrade surfaces

    Posted 10-30-2020 05:34

    Thanks Matt!  I think that's another issue I was doing incorrectly.  I thought each subgrade linestring had to be closed within itself.  And when I did that, I was creating shared lines on top of other subgrades.  I see now that the Site Improvements boundaries act more like "petitions"  as long as you check the box "contains potential boundary lines".  

  • 8.  Re: Multiple subgrade surfaces

    Posted 11-02-2020 18:14

    To apply Site Improvements to create Subgrade Surfaces you do not even have to use the Takeoff Workflows. The rules are as follows


    1. The lines that you want to use as a boundary for a Site Improvement have to be a part of the surface to which you are applying the Site Improvements. 
    2. The lines that you want to use as a boundary for a Site Improvement have to be 3D and will need to be linestrings. If you have CAD Lines or Polylines, you can convert all of the lines in one pass using the Convert to Linestring TML Command (Use TML Status from Rockpile Solutions website to download and install the TMLs on your PC if you do not already have them).
    3. The lines that you want to use as a boundary for a site improvement have to be tagged in their properties as Sharp and Texture Boundary in the Surface Sharpness field


    The lines do not have to be closed polygon areas, but collectively a group of lines that meet the criteria above need to form a closed area - i.e. you can have 4 separate lines that touch or cross at the corners of a square, and provided that there are no gaps the Site Improvement will flood to the square and set the Site Improvement Property on that area.


    The application of the Site Improvement and the creation of the Subgrade Model takes care of the minor offsets required to eliminate vertical step flags in the subgrade model. You do not have to offset the lines to work this process. That will likely cause more problems than adding any value.


    The Materials that make up the Site Improvements will normally be defined in the Earthen Select Category or a User Defined Category in the Materials and Site Improvement Manager (MSI Manager). e.g. Asphalt, Concrete, Sand, Gravel, Aggregate etc.


    The Site Improvements will be defined in Categories of Site Improvement within the MSI Manager. A Site Improvement is the stack of materials that is to be found in that area - e.g. a Gravel or Aggregate Base, a Sand Layer and an Asphalt or Concrete Layer. The Site Improvement defines the stack of Materials and the thickness of each material layer.


    To apply Site Improvements to a Surface Model, use either the Takeoff work processes, but if you aren't doing Takeoff and only want a subgrade adjusted model, then you can use the Apply Surface Site Improvements Command. This will ask you for the Surface to which you want to apply the Site Improvements. It will ask you for a Name for the Site Improvement e.g. Road Pavement, it will ask you for a layer - each Site Improvement is represented by a point that carries the Site Improvement Attributes. The Point will be placed on this layer. I use SITE - SI Markers as my layer for this and I have it in the 99 - SITE DATA layer group. It will ask you to select the SIte Improvement (from the list of Site Improvements that you have defined in the MSI Manager and it will then ask you for a location for the Site Improvement - place the point in the area that you want the Site Improvement to be applied - eg the Road or the sidewalk or building pad etc. You will see the color that you defined for the Site Improvement in the MSI Manager will flood the area to indicate the area that has the Site Improvement - if it floods out of the area then you have one of the following issues


    1. One or more of your lines does not have the Sharp and Surface Texture applied
    2. One or more of your lines is not 3D
    3. One or more of your lines is not included in the surface model (use the Selection Set - Members of Surface XXX in View Filter Manager to check that)
    4. You have a gap between lines where the Site Improvement flooding can squeeze through and flood an adjacent area.


    Once you have applied all of your Site Improvements, you can use the Create Subgrade Surface command to create the Subgrade Adjusted Surface for any Material Layer in the Site Improvements. Note that the Material Layers will be like the Top or Bottom of Sand or Aggregate or Asphalt or Gravel etc. Typically model the Bottom of the Material Layers that you need surfaces for. The surface created will be either a continuous surface or a surface made up of islands e.g. if you did base of Sod for Parking Islands, you would have one surface with lots of islands - one for each parking island. 


    If you just want the bottom of the lowest subgrade in each area where you applied a Site Improvement and Finished Grade in between where no Site Improvements were applied, then use the Bottom of Engineered Materials option to create that surface.


    Note that if all you care about is the base of subgrade, then all you need in the MSI Library is one Material called Subgrade and then a number of Site Improvements, one for each total depth of subgrade materials - so for example an area covered in 6" Asphalt, 4" Sand, 6" Aggregate would be a total of 16" (1.33') thick. So a Subgrade called Subgrade 16" which has one layer of Material Subgrade that is 16" thick would cover the need. Then you would just create Subgrades like Subgrade 6", Subgrade 10" Subgrade 12" Subgrade 16" and then just apply the one that is applicable in each area, then create the Subgrade Surface using the Bottom of Engineered Materials and you will be good to go.


    This whole process is captured in the video download link below





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  • 9.  Re: Multiple subgrade surfaces

    Posted 11-19-2020 10:25

    Great, thanks Alan, as always you provide a great in-depth look at the program.  I'm picking up a lot watching a bunch of your videos.