Superelevation Part 3: Spilling the Gutters

In this passage we will focus on Curb and Gutter subassembly settings, and how they can react to design at full superelevation in the middle of a curve.  Below the curb was left in its defaults:

• Gutter Slope Method:  Outside Lane Slope 
• Gutter Slope Direction: Away from Crown

Notice how the Gutter Slopes, it varies from catching or spilling on the High and Low ends:
 
One option is to set a “Fixed” slope and forcing the gutter to a consistent grade on the left/right and high/low sides.  Causing water to be collected in the gutter, ignoring superelevation.
 
Perhaps, the desired design option is to alternate catching and spilling water from the gutter:
First, the INSIDE Curbs: Gutter Slope Direction is set to “Towards Crown”
 
Next, the OUTSIDE Curbs: Gutter Slope Direction is left on “Away from Crown”

This mixed configuration will make the gutter will spill and catch correctly on the High and Low side for both the Left and Right type of curves.

The next post will explore the use of Superelevation values to shoulder subassemblies:
•    Part 4:  Rolling off the Shoulders

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About the Author

Civil Applications Expert<br><br>As an Applications Expert, Leo is responsible for supporting, training and implementation of software for survey and civil engineering professionals. He has more than 17 years of experience helping large and small, public and private clients in the eastern United States.

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