The following videos show you how to model ditches where the ditch data is provided as a PGL line (a series of elevations at different stations along a highway) but no offsets are provided. We know where the hinge line is for the ditch foreslope, and we know we want a 3:1 slope into the ditch and then the ditch needs to be a flat bottom 4’ wide before the sideslope back out to existing at 3:1
The video below shows how to model this using 3 different methods
- Using a Material Layer for the Ditch Profile Surface and the side slope to Material Layer instruction
- Using a slope slope intersection instruction
- Using a slope to elevation instruction and an elevation table for the PGL of the Ditch
The methods shown in 1&2 both use the PGL to define a Vertical Alignment on the HAL of the Road to define the Ditch profile line. This shows how to create multiple vertical alignments and then how to add the additional vertical alignments to the corridor model as reference lines that then provide you anchor nodes in the corridor template that can be used to create the surface elements required to model the ditch.
This video shows how to adjust a ditch profile line to accommodate crossing culvert lines that have a different elevation to the ditch profile