ROUNDABOUTS SUPERELEVATION

Standard design practice for a roundabout is to apply a standard crossfall across the roundabout circulatory carriageway generally 2 to 2.5%. The approach lanes would be set to standard crossfalls in the vicinity to the roundabout entry and exits to provide a smooth tie in with the roundabout circulatory carriageway .

Thanks Jason .
It is not a standard roundabout. It is a special case and superelevation varies within the roundabout. It's possible modify and apply the supetelevation in the roundabout.
Thanks for your help.

Thanks Jason .
It is not a standard roundabout. It is a special case and superelevation varies within the roundabout. It's possible modify and apply the supetelevation in the roundabout.
Thanks for your help.

Superelevation rules won't be of use as it is a single horizontal radius. You can manually add the required slopes across the roundabout circulatory carriageway using the Profile by Slope from Element and Profile by Variable Slope From Element applied at the required locations. Create a complex profile of the vertical elements to have a single profile for the horizontal element.

Thanks Jason .

But it is possible.

When I work with roundabouts radius> 50m I can do it without problems.

The problem is when working with a roundabouts radius < 50m .

In my case 30m .

When I create a superelevation section, a bandwidth of 100 m ( -50, + 50) is generated.

I think that's because I did not draw well for a 30m radius roundabout .

Is there a variable that controls the bandwidth generate and can be modified by the user to put a value < 30m ?

Thank you very much .

The operational speeds of Roundabouts should eliminate any need for superelevation. What constitutes a non-standard roundabout? Your first picture looks pretty standard.

I have checked that here and have noticed the same. It appears to be a fixed setting for that. The superelevation sections/lanes wouldn't have been intended for use with small single elements and was set up for multi element alignments to automatically generate superelevation based on a rules file.

For what you are intending on doing a rules file will be of no use and you will have to manually set the superelevation which negates the purpose of the superelevation tool.

From a designer perspective the design process I would use would be as below.

1. Create the roundabout crown element and edge roundabout circulatory carriageway elements.
2. Apply a vertical profile to the crown.
3. Transfer levels to the roundabout circulatory carriageway elements from the crown using Profile by Slope from Element and Profile by Variable Slope From Element at the required values and locations.