Trimble Business Center

I did a takeoff for a client building a precast bridge that contains earthwork under the road and above the creekbed.  I stopped my takeoff at both ends of the bridge and manually calculated quantities for the earthwork under the road and above the creek.  Does anyone have any suggestions on how to model the earthwork and get quantities?  Below is a detail of the bridge where there is fill between both sides and under the road.

Interesting Topic. I am curious about this myself. Definitely one of those hybrid grey areas. 

What about creating a separate corridor for this bridge area? You could use templates to start and stop the main alignment at the bridge ends, like you mentioned you did, and then use this second corridor to get the quantities for under the bridge. 

You would have 2 corridor takeoff reports but that wouldn't be the worst thing because it a different type of work being performed for each respective "corridor". 

I think that would be a good way to do it.  One of my biggest questions is how to model the bottom of the fill material that is confined within the precast bridge. Maybe create an existing ground surface that could be the precast arch and sides?  I'm not sure how to model that arch in TBC.  Maybe just a bunch of slope-offset lines in a tight enough grouping to simulate a 3D arch?

I had the thought of creating an alignment perpendicular to the road centerline at the center of the bridge elevated to the apex of the arch and treating it like a very short road with a parabolic crown and side slopes.  What do you think?

I think the side slope tool would work great for this application. That or the vertical design tool. 

Is the purpose of the modeling the arc to get concrete quantities for the bridge? I am not fully following why you would need to model the arc. 

The area in red represents the fill material on top of the precast arch  The red horizontal line represents the bottom of the road subgrade.  The areas outside of the red are covered in the takeoff for the road approaching on either side.  I like your quick 3D arc.

Gotcha. So it is not a solid concrete precast piece. That makes sense.

I would give the create vertical design a go. I was able to whip that up in a few seconds and it gives good results. Then you can either do an earthwork report or add the vertical design as a surface in a corridor and run the quantities for the rock and fill all in one shot. I would probably just use a tighter station interval with it being a unique shape like that. 

That is what I am going to try.

I have a material in my MSIM called 'AIR' for basements and odd stuff like this.  Anything not square/cubic won't work well under a standard takeoff site improvement, but in corridors could get you close if you plug in the vertical arcs at the bottom of the bridge in as reference lines.  

Probably all overkill for a quantity so small.  

I was able to come up with a rudimentary idea - based on the detail provided - of what I believe you were going for using the Vertical Design Tool in a very short amount of time(about 10 minutes) using the Vertical Design Tool. Had to use some geometry to figure out the VPI elevation but creating an arc on Vertical Design was very easy using the VPI instruction. Creating a plane with the Vertical Design was what I used for a Finished Grade surface and ran Surface to Surface Earthwork Report. Hopefully this helps.

I just can't seem to wrap my head around creating an arc in Vertical Design.  I did it the old fashioned way (calculating distance/offset from the high point and creating offset lines and then connecting the endpoints), but can't seem to replicate that in my head to give instructions in Vertical Design.  Thank you for all the help everyone.

Let me know if this helps.

Thank you for that.  I appreciate the time you put into this to help me out.