Alignment Design Check Examples

Following are some examples of design check syntax.

The following examples demonstrate the type of parameters that can be validated using design checks. Use the examples as a basis to create your own custom design checks.

Note: Several design checks are included in the AutoCAD Civil 3D templates in the ToolspaceSettingsAlignment and ProfileDesign Checks collections.

Minimum Tangent Length

This design check validates that a tangent is a minimum specified length.

Name	Tangent Length >= 100
Type	Line
Formula	{Tangent Length}>=100
Formula Description	Tangents must be greater than or equal to 100.

Minimum Tangent Length at a Design Speed

This design check validates that a minimum tangent length is used at a given design speed.

Name	Tangent Length >= 100 @ 45mph
Type	Line
Formula	IF({Design Speed}>=45,Length>=100,1)
Formula Description	If the design speed is greater than or equal to 45, the tangent length must be greater than or equal to 100. Note: In the IF function, the ending 1 indicates that if the entity meets both the design speed and length conditions, a true value is returned. A true value means that the entity meets the design check, and no warning is issued. If the entity does not meet one or both of the conditions of the design check, a warning is issued.

Design Speed On Curve Radius

This design check validates that a minimum curve radius is used at a given design speed. This design check is relatively complex, and combines several formulas into a single design check.

In this example, the minimum curve radius at eight separate design speeds is validated. When applied to an alignment, the design check checks the curve design speed value, and then validates that the radius is greater than or equal to the specified value.

Name	Design Speeds On Curve Radii (Multiple)
Type	Curve
Formula	IF({Design Speed}>=120,Radius>=750, IF({Design Speed}>=100,Radius>=500, IF({Design Speed}>=80,Radius>=300, IF({Design Speed}>=70,Radius>=200, IF({Design Speed}>=60,Radius>=125, IF({Design Speed}>=50,Radius>=80, IF({Design Speed}>=40,Radius>=50, IF({Design Speed}>=30,Radius>=30, Radius>= 0))))))))
Formula Description	If the design speed is greater than or equal to one of the specified speed values, the radius must be greater than or equal to the specified radius value for that speed.

Design Speed On Tangent Length

This design check validates that the tangent length is within a specified range at a given design speed. This design check is relatively complex, and combines a several formulas into a single design check.

In this example, tangent length at five separate design speeds is validated. When applied to an alignment, the design check checks the tangent design speed value, and then validates that the tangent length is within the specified range.

Name	Design Speeds On Tangent Lengths (Multiple)
Type	Line
Formula	IF({Design Speed}>=120,(2000>=Length)*(Length>=500), IF({Design Speed}>=100,(2000>=Length)*(Length>=400), IF({Design Speed}>=80,(1500>=Length)*(Length>=350), IF({Design Speed}>=70,(1200>=Length)*(Length>=300), IF({Design Speed}>=60,(1000>=Length)*(Length>=250),Length>=0)))))
Formula Description	If the design speed is greater than or equal to one of the specified speed values, the tangent length value must be between the maximum and minimum values specified for that speed.