Trimble Business Center

This question is part of the blog post I started about dynamic modeling:

Dynamic Modeling - Takeoff to Surface Model 

Modeling Cul-De-Sacs with no Center island

After some further investigation, it looks like the Cul-De-Sac tool does not support Cul-De-Sacs that do not have center islands, such as the Cul-De-Sacs in the sample data provided. 

If I add a center island, I can get the cross slope of the lane to be -2%, but it models the center of the Cul-De-Sac incorrectly because it creates and island and there should not be one. I couldn't not find a way to fake a no island using the tool. 

Enhancement Request:

1. I think there should be an addition to island type: no center island. this would keep the Cul-De-Sac flush from the the center to the edge of lane/shoulder carry the desired lane cross slope. 

1. There should also be a new line command that allows you to set the island as a void. This would apply a boundary line to the Cul-DeSac and allow the user to manually model the center of the Cul-De-Sac.

• island - would be the default
•  void
  • This would allow create a void at the center of the Cul-De-Sac and allow the user to add any customization they may need for the center island

         This can be accomplished by adding a boundary lines, one the exterior of the Cul-De-Sac and one the center island of the Cul-De-Sac, but the user could lose some of the dynamic capabilities if the shape of the island and Cul-De-Sac changes

Thank you.

Cross slope example:

Examples of projects with these parameters( no center island):

Pat

This is a Design Tool not a Data Prep tool at this stage.

We are looking at using this tool in "revese", i.e. provide it the Alignment, Linework and known elevations and let it compute the best solution from the data provided. I passed the link over to the developers and they are looking at it and I am waiting for a response from them before I give you a more detailed answer here.  

From a Design perspective you have the alignment properties that lock in the Vertical for the center point. You have the Design approach road to the Culdesac that controls the elevations / slopes at the entry point, and then you enter desired lane cross slope - and it tries to fit based on that - but as you say you do not get a locked in -2% slope (in reality the slope cannot be -2% all the way around the culdesac - it has to vary, and the culdesac also has to drain - but the engineer has worked out what they want to do with the water and specified slopes and elevations accordingly - which is not necessarily ever going to fit with what this calculation does (where it doesnt know where the water is going to end up - the Cul de sac once "Designed" will dictate where the water will end up and therefore where to place an Outlet / Inlet structure etc. This is not at all what in construction we have to do - if the Engineer changes all of the Elevations so that the culdesac slopes in a different way, then we have to fit in with that desire (hence the reverse approach), which is designed to "fill in the gaps" and try to make the Engineers data work.

When we get round to detailed field testing on that I will let you know - it is currently conceptual work only and is some way out there in the future (I cannot say that we will ever release etc.)

In the example you show - the desired cross slope is not radial in the Culdesac - it is a Cross Slope across the Cul De Sac if I am interpreting the drawing correctly. This should be modeled with Data Prep Tools I guess at this time.

Alan