Option

Description

Type

You can select either a 3-way or a 4-way junction. The schematic diagram update to show the layout.

3 Way

4 Way

Crossfall

The crossfall in the roundabout can be Crown, Crossfall or Draped.

Crown

The roundabout surface is crested, allowing some of the drainage to flow to the inner circle.

Crossfall

The roundabout surface is graded to direct all the drainage to the outside of the roundabout.

Draped

The roundabout surface will not be graded. Instead, Civil Designer will simply drape the roundabout centre island onto the main road.

Kerb for circle inside

Apply Kerb

Select this checkbox to add a kerb to the inner circle and then click the button below to display the Kerb Selector.

Radius (RIn)

3-Way only. Specify the radius of the bell mouth at the back of the roundabout, as indicated on the schematic.

Radius (ROut)

3-Way only. Specify the radius of the bell mouth at the back of the roundabout, as indicated on the schematic.

Radius (R)

Specify the radius of the inner circle in m.

Lane Width (L)

Specify the lane width in the roundabout in m.

Crossfall (e)

Specify the crossfall as a percentage in the roundabout.

Coordination

Interval (m)

The strings along the bell-mouths will be coordinated using this interval.

Point Prefix

Each bell-mouth point will have this prefix when you translate the intersection to a DTM surface, or when you opt to display the intersection list during plan plotting.

Minimum Bellmouth radius

Specify a minimum bellmouth radius for the incoming roads. If this value is not set, the bellmouth radius will be defined by a circle tangential to the edges of the incoming roads and the outer roundabout circle.