This is a road superelevation example using Section3D.
If you haven't installed the Section3D subassembly click on the button below to view How to Install Section3D Subassembly:



RoadSuperelevation-Completed.dwg : Sample Civil 3D 2010 Dwg File used for this tutorial
Full-SuperElevation-Template.zip : Section3D Full Template (fully reusable and modifiable) created in this tutorial

In this tutorial you will learn how to apply the superelevation to a roadway in Section3D. Superelevation can be tricky not because of the superelevation itself but because other links such as the granualr and subgrade(datum) links must coordinate with the superelevation of the pavement surface, especially during the transitioning of lane from a normal(tangent) section to the fully superelevated section. The lane shoulder crossfall is another variable where the relationship between the lane and shoulder crossfalls may not be always linear. This excercise is based on the following superelevation standard:




It is assumed that you know how to create the superelevation data from the Alignment Properties dialog box as shown below.



You must also know how to create a simple Road template from scratch. If you haven't completed the basic Section3D excercise please complete the Section3D 101 first from the following link before proceding with this excercise. Otherwise please create the Section3D template as shown below.
Section3D 101 (Basic Concept)




You may want to display the slope for certain links in Section3D for this excercise, and you can do this by entering the min. slope value from the Section3D Viewer Display Settings.



Please view the video by clicking the button below to understand how the relate and inherit slopes/grades works in Section3D. You can create your own custom .REL table under the Section3D REL folder. Simply create a text file with the slope relationship defined (make sure that the two rows have the same number of fields with comma as a delimiter) and rename it with .REL extension instead of .TXT



After creating the full lane (by mirroring the half template) you can assign the slope relationship between any two links. For example, the slope of the road shoulder (point 3) depends on the slope of the edge of pavement (point 2) for the left side. You can establish this relationship by Select Point 3 -> Right mouse click -> Edit Dialog -> Select S(Slope) -> Right mouse click -> Inherit/Relate.



The LANE-SHOULDER relationship table is derived from the LANE-SHOULDER.REL (text) file under the REL directory of Section3D. You can create a new or modify existing REL file since it is a comma delimited text file (open in notepad). The relation table can be used for any slope-to-slope relationship between two links. Increasing the vertical exaggeration to 5 from the Display Settings may be a good idea at this point before proceding with the next steps.



The superelevation table simply states the relative values of Point 3 depending on the value of Point 2. Any other values in between are interpolated linearly. This type of table is often called 'Superelevation Table'. You will note that the relationship is not linear and the fundamental idea is to provide a smooth transition of the break(roll-over) point during superelevation.



You can assign the same relation table on the right lane between point 24 and point 25.



The next relationship is between the edge of pavement and the subgrade(datum) break point below. This table is derived from the file LANE-SUBGRADE.REL from the REL directory.



Apply the relation table to the right lane subgrade break point (point 31).



The third (and the last) relation table (LANESUBGRADE-SHOULDERSUBGRADE.REL) is between Point 9 and Point 10. This point represents the high/break point of the Subgrade at full superelevation. We are assumming the design constraint that the subgrade slope must always maintain the minimum 3%.



Assign the three tables to each side and the final code should read as shown below:



You can save the template with the assignment of these relation tables. The final step is the assigning of the actual superelevation data stored in the Civil 3D alignment object. The edge of pavement point is the first point which triggers the coordination of others defined by the relation tables.



Civil 3D has two superelvation values (inside and outside). You can select LISE for the left edge of pavement.



You can select the RISE for the right edge of pavement.



After mapping the center point (point 1) to the alignment and profile (Select Point 1 -> Right Mouse click -> Edit Dialog ->...) apply the current X-section to a stationing range.



Another useful Section3D feature is the ability to superimpose the previouis and next sections from the Section3D Viewer Status bar. You can also export a group of sections as image files so you can e-mail them to others who may not have AutoCAD to view.



The next six images exported from Section3D show the gradual transitioning of superelevated sections in detail. You can check whether the design constaints have been met.








This is the fully superelevation Civil 3D section from the corridor. Note that only one shape was created in Section3D.



Step16:



Step17