Trimble Business Center

I have created a Finished Surface for a Road Corridor with a number of conditions. This has resulted in varying side slopes. I now have to create a Subgrade surface that is say X cms below the Carriageway, extend sideways following the slope table. I have to provide for a 15Cm Granular fill at the varying side slope. This is throwing some challenges. I have attached files that explain the situation. Could some one help me out?

Some solutions I was considering were:

1. To extract slope information from the Finished surface and use that as a shared table.

2. To offset the Finished Surface and then us this as the terminating surface for the Subgrade layer.

I do not know if such features are available in TBC.

Hope to receive some advise.

Thanks.

All you need to do is use the slope slope instruction and select the slope node you want to start at for example at left carriage inside right shoulder, and then where it asks for the slope next, hit the drop down options and select "node to node" and select your finish grade right Shoulder and Finish Grade Left Shoulder and it will basically just mimic what the slope is between those 2 nodes so that way you don't have to recreate all the tables and what not you created in the finish grade model, then to complete the instruction select the 2nd slope node, which for example would be the Left finish Grade Shoulder ( in your case, you will have to create a "ghost node with no material layer selected that has the offset of your slope 15cm for granular fill inside of the finish grade left shoulder) and then for the slope next select the option "node to node" again and select the left finish grade shoulder node for the first node and then select the hinge point or the toe of your slope for the second node, now what this is going to do is mimic whatever slope those 2 nodes create however you built the finish grade model and it will project that slope downwards from your offset ghost node and it will intersect with the first slope you put in that mimics your left cross slope from the right shoulder of the left carriageway and create a node at that intersection point. Then just keep repeating the use of the slope slope instruction where ever you need to create subgrade surfaces and mimic your finish grade slopes. you can also select the node to node option in other instructions like offset/slope or offset/elevation for the offset command and it will use whatever the offset is between 2 particular sets of nodes and mimic that. Without the slope slope instruction creating subgrade surfaces would be darn near impossible and extremely time consuming.

Thanks for the response.

Sounds simple!! But there are complications as the slope nodes are all different because of various conditions imposed for the side slope depending on the ROW, cut / fill situation etc.Attached *.vce file makes it clear. Could you please try that once?

The solution I have found is a little Hybrid. I export the finished surface to an XML file and import the XML file to Terramodel. In Terramodel I make this surface the "Existing Surface", I offset the VAL by the desired value MINUS 15Cm. Then create a "Finished" surface with a segment terminating at the above XML surface at the side slope. Generate a DTM of the "Finished" surface and merge the Existing and Finished Surfaces in Terramodel. Now, I have a Surface which is 15 Cm above the desired subgrade Surface.

This surface is used by me in Machine Control System. Here, I impose a 15Cm perpendicular offset for the subgrade surface to make the machine get me the desired surface.

May be my approach is a little circuitous. But is giving me desired results on site.

I welcome any workflow that is simpler.

Do please revert to me.

Thanks a lot.

Ok so you’ve used conditional instructions I’m your corridor to create the side slope segments? I have not opened up your .vce file yet but I will tomorrow morning when I get to my office.

I like your creativity on how you went about creating your desired sub grade surface. Sometimes you really have to think outside the box with TBC-HCE in order to get what you want as every single civil construction project is unique in itself.

The majority of the time I am building models is for a purpose of earthwork quantities and I like to be able to have all of the quantities reported on one single corridor earthwork report if possible so I’ve gotten a lot of experience getting creative and working around getting the material layers and associated materials above each layer for the sub grade surfaces to get created like the typical sections show and getting them to report volumes correctly. Conditional instructions can surely complicate things further.  I’ve never had a problem losing nodes in a corridor from using conditional instructions from what I can remember but they might have been really simple conditional instructions.  Let me see what I can come up with in the morning.

Without looking at your vce file, the best way I can think about making that work is to take your finished grade corridor surface and explode it. Then you should get multiple linestrings created from the multitudes of nodes at your hinge point or toe of your variable slope.

Then I would join all those linestrings into 1 continuous linestring ( being very careful that they connect in the manner that my corridor is transitioning and interpolating the nodes) then I would add the 3D Linestring as a reference line into the same corridor. Now that line becomes a node in your template view along the entire stretch of your corridor mimicking the exact same location as your variable slope nodes except this new node is not part of any surfaces in your corridor yet so it won’t have any effect on your model yet. Now when you use the slope slope template instruction while creating your subgrade surface, you can select the node that was created by the reference linestring you added. That node should always be there and it should always be right where you want it to be because it was essentially created from all of the various variable slope nodes in your finish grade corridor surface.

Same thought process as your solution - use the finish grade surface you’ve already successfully created to your advantage.

Let me know if you see problems with adding a reference line. I’ll open your vce project first thing in the morning and get back to you.

Cheers

Bryan Gallagher

Sent from my iPhone

Thanks a lot for your response. Will wait for your update.

Thanks.

On Sat, Jan 5, 2019 at 9:38 AM bgallagher@colaska.com <trimble@jiveon.com>

I went in and studied your corridor to get a better understanding and then I exploded the finished surface and joined all the 3D polylines of the nodes at the hinge point or DB and Toe of Slope and added it as a reference line so at least I can intercept the subgrade with the finish slope if needed. Then I created the subgrade layer and created a ghost node about a half meter above the slope intercept that was offset from the 1:6 slope by .92 meters towards CL. .92 meters in horizontally is the distance with a 1:6 slope you need to achieve a perpendicular offset of .15 from the finish 16slope. then I used a slope to slope instructions using the ghost node as the second slope node and the slope of node to node of the Finish SHD and the 3d reference line at the DB or Catch. This created a Subgrade slope offset .15 meters perpendicular to the finish slope. However I do see your challenge of your side slope being variable because the .92m offset will change when the slope changes. I noticed that at least on project right it is a 1:6 for the vast majority of the time so with some tables or added templates it could be achieved. I think for as far as what you are needing the subgrade surface for which it sounds like is mostly machine control models then the way you did it by integrating Terramodel and just using a .15 m offset is probably the more efficient way. if you were needing accurate of quantities of subgrade and the granular fill then you would probably need to spend the time making for tables and or creating reference lines and maybe extra templates here and there.

Thanks for all your efforts. 

We will keep exploring. May be TBC guys will come up with a better solution in their later releases or patches.

Regards.