This subassembly inserts a travel lane, applying the Outside Lane superelevation slope value, and widens the pavement at superelevated regions.
It can be used for most undivided roads, or divided roads with no lane slope break on either side. It may also be used for the outside lanes of divided crowned or broken-back highways. The pavement structure follows the standards described in “Pavement Structure on Paved Sections” in the AutoCAD Civil 3D Help. The only difference between this subassembly and the LaneOutsideSuper subassembly is that this subassembly also widens the pavement width in superelevated regions of the corridor.
The attachment point is (a) at the inside edge of lane on finished grade, if the insertion point is Crown, or (b) at the outside edge of travel way,if the insertion point is at the edge of travel way. This component can be attached to either the left or right side.
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. For more information, see in the AutoCAD Civil 3D User’s Guide.
The Outside Lane superelevation slope is obtained from the superelevation specifications for the baseline alignment. Starting at the attachment point, a finish grade surface and parallel subgrade are inserted using the given width, depth, and the superelevation slope. Vertical links close the shape at either end of the lane.
If the current station is within a superelevated region, then the lane width value is calculated as follows:
Width = Default Width + Pavement Widening
R = Radius of the alignment at full superelevation
L = Length of wheelbase including the front overhang
The lane should be widened starting from the "End Normal Crown" and by the time "full super" station lane should be "default width + pavement widening". If spirals are used, typically this widening transition length is equal to the length of the spiral.
The key steps in completing this conditional subassembly are:
- Set pavement widening to zero.
- Get the default width from parameters.
- Verify whether a station is in Superelevation zone or not.
- If Yes, then find the radius of curvature at full super station (not current station).
- Compute the pavement widening value from the equation mentioned in the spec (ExtraW).
- Find out the station value of “End Normal Crown” in this region; and similarly find station value of “Full Super”; find the difference as length along alignment to distribute (L).
- Divide ExtraW by L and get that factor RateW.
- For the current station, find the difference between “end normal crown” station and current station (DeltaL).
- Multiply RateW by DeltaL to get DeltaW for the current station.
- Add the DeltaW to the default Width provided in the subassembly properties.
- Hence, the new width at the current station is = Width+DeltaW.
The DeltaW is the only parameter (note that it is not an input parameter) that is shown in the following diagram.
The preceding diagram is not accurate, but indicative. The black line represents centerline and the blue lines on left and right denotes edges of different lanes on right and left sides (after design). The light (gray) colored lines in the diagram indicate original right and left edges. The deviation of the designed edges is due to the provision of extra widening.
If an offset horizontal alignment name is assigned to the Width during corridor modeling, the width of the lane will vary to match the offset of the alignment.
Superelevation Axis of Rotation Support
This subassembly can be used with superelevation axis of rotation pivot points only in cases when the parent assembly is built out from the baseline.
In layout mode, this subassembly displays all lane links using the width and depth input parameters at a -2% slope.
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.
