take the edge off Roads, Drains

We’ve got the planes positioned and the profiles extracted… all we have to now is

• create the design profile and
• build the finished corridor.

This is a follow on from previous posts:

“Widen at Grade.. the concept”
“ref planes 002 a practical example (part 1)”

[More:]

Design the finished profile…

We’ve got the 2 reference planes in place so we extract a profile of our design string showing these (Cyan colour in diagram below)

We can design most of our new profile based on the planes, just snapping to the cyan lines. For the Kerb Return section (Red), we use some design curves for a smooth transition.
This is our finished design string for the new kerb.

Build the Finished Corridor…

We build a corridor using the following:

1 Baseline String
1 Assmebly
2 regions

For the assembly, we’ve used the superelevation subassembly on the right as this component is going to be stretched and adjusted to meet the existing roads. We’ve also put a simple kerb & gutter on the left with a batter.

We build the corridor using the Bus Bay alignment and the profile we just designed. Instead of running the assembly to the end of the alignment, we stop it where the 2 saw-cut alignments meet (see the green region in the diagrams on the right). This is Region 1 - we set the targets of the right hand lane to the Saw_Cut_Main alignment and the profile extracted from the survey of the existing road. This ensures the new lane marries into the existing lane properly.

Region 2 starts off where region 1 ended - it’s the same thing, only the targets for the right hand lane are the alignment and profile from Saw_Cut_Side.

This produces the corridor in the screen capture so we can go use the standard procedures to create surfaces for volumes etc etc.

Conclusion:

I like this example as it is reasonably simple and illustrates the concepts of Reference Planes nicely.
With 2009, we can use feature lines as well and combine in some grading objects.
I’ve put in an AU paper on all this - “Roundabout Reconstruction Using Corridor + Grading Objects” - it’s all funky and updated for 2009 so if you’re doing the voting thing that everyone is talking about these days, it’ll be an interesting session.

cheers,
SeanT