This subassembly creates a cross-sectional representation of a depressed median with inside shoulders, using extended termination of shoulder subbase.
It supports superelevation pivoting about the attachment point at the centerline, or about the attachment point elevation at the inside edges-of-traveled-way. The pavement structure on the paved portions of the shoulder follows the standards described in "Pavement Structure of Paved Sections" in the AutoCAD Civil 3D Help.
The attachment point is above the centerline of the ditch. The location of the median links relative to the attachment point varies depending on the pivot method, and in some cases, the median widths and lane slopes. The attachment point is typically placed on the baseline alignment at the design profile elevation.
Note: All dimensions are in meters or feet unless otherwise noted. All slopes are in run-over-rise form (for example, 4 : 1) unless indicated as a percent slope with a “%” sign.
This section lists the parameters in this subassembly that can be mapped to one or more target objects, such as a surface, alignment, or profile object in a drawing. For more information, see in the AutoCAD Civil 3D User’s Guide Help.
| Parameter | Description | Type |
|---|---|---|
Superelevation Axis of Rotation |
Indicates whether the subassembly supports the axis of rotation calculation. To view a description of the parameter, in the Properties window, hover the cursor over the parameter. For more information, see Profile Grade Line Adjustments During Superelevation. |
Static (Description) |
This subassembly cannot be inserted separately for the left and right sides. It builds the median to both sides of the attachment point.
The median can be configured to have the pivot point at the centerline, or at the inside edges of traveled ways. If Centerline Pivot is used, the left and right outside lane superelevation slopes are obtained from the baseline’s superelevation specifications, and the elevations of the inside edges-of-traveled-ways are calculated by applying these slopes to the left and right median widths from the attachment point. If Centerline Pivot is not used, the edges-of-traveled-ways are held to the elevation of the attachment point.
Superelevation or turning lanes may cause the top of the ditch slopes to be at different elevations on the left and right sides, resulting in an asymmetrical ditch. There are two options for handling this situation. If Hold Ditch Slopes is set to True, then the given ditch slopes are held constant on both sides, which shifts the bottom of ditch away from the centerline towards the lower side. If set to False, the ditch bottom is centered about the median centerline, the given slope is held on the lower side, and the slope is adjusted to match on the higher side.
The paved shoulders follow the slopes defined for the left and right inside shoulder slopes for the baseline alignment’s superelevation specifications. These slopes are applied inward from the inside edges of traveled ways. The subbase surfaces follows the same slope as the finished grade, and is extended inwards to the intersections with the ditch slopes.
Superelevation Axis of Rotation Support
This subassembly works only with Roadway Types that have a Pivot Method of Median Edges and a Median Treatment of Maintain Median Shape. If you use this subassembly with any other Pivot Method or with Distorted Median Treatment, it will produce a result equivalent to Median Edges with Maintain Median Shape.
In layout mode, this subassembly calculates and displays the median and shoulders based on the input parameters given, with lane slopes of -2%, paved shoulder slopes of -5%, and turning lane widths of zero.
The following table lists the point, link, and shape codes for this subassembly that have codes assigned to them. Point, link, or shape codes for this subassembly that do not have codes assigned are not included in this table.
