Design criteria files are another way of having Civil 3D check your design as you go. From an end-user standpoint, there is not much difference between a design check set and design criteria file: they’re both something you assign to your alignment so that certain design parameters can be checked. From a setup standpoint, they’re quite different. Design check sets are a group of design checks that are relatively simple and are managed through the Settings tab of the Toolspace. A design criteria file is a single file, and it is potentially much more sophisticated. There is a special tool for editing design criteria files called the Design Criteria Editor. Civil 3D comes with AASHTO design criteria files that can be used as is or copied and modified to meet local requirements. Autodesk also provides numerous country kits that include even more design criteria files that meet the requirements of various design authorities around the world.
Tips :AASHTO stands for the American Association of State Highway and Transportation Officials. It is the basis for many of the state DOT standards in the United States.
To apply a design criteria file to an alignment and then adjust the design of the alignment based on what is reported, follow these steps:
- Open the drawing named Design Criteria Files.dwg located in the Chapter 05 class data folder. Note that currently there is only one warning symbol shown for the Jordan Court alignment.
- Click the Jordan Court alignment, and select Alignment Properties on the ribbon.
- Click the Design Criteria tab. Check the box next to Use design criteria file.
- Click the button to the right of the file path, and select the file named Autodesk Civil 3D Imperial (2004) Roadway Design Standards.xml (Autodesk Civil 3D Metric (2004) Roadway Design Standards.xml). Click Open.
- Uncheck the box next to Use design check set.
- Click OK and press Esc to clear the grips. New warning symbols appear on the first, second, and fourth curves. As you can see, the design criteria file is a bit more stringent than the design check set of the previous exercise.
- Hover your cursor over the warning symbol farthest to the north. The tooltip informs you that the required radius is 154' (47m).
- Select the alignment, and click Geometry Editor on the ribbon.
- Click Alignment Grid View on the Alignment Layout Tools toolbar.
- Note that the Minimum Radius is listed in Panorama. Change the radius of items 2, 3, and 7 to 155 (48). Do not edit item 5; it should remain set to 50' (15m).
- Close Panorama and observe the change to the alignment. With the exception of one curve, the alignment meets the requirements of both the design criteria file and the design check set.
You Have the Power
Design check sets and design criteria files do not change your design. They simply tell you when one of the rules has been broken. Depending on many factors, there will be times when you fix the issue to satisfy the rule and times when you don’t. In the previous case of the 50' (15m) radius, you know that Phase II of the project will create a T intersection at this location, which makes the sharp turn OK.
