2.7.2. Elements of a vertical parabolic curve

Try these first

1. 1.

   What is a vertical curve?

   Hint

   Think about the connection between grades.

2. 2.

   Define a summit curve.

   Hint

   What happens to the road at the top?

3. 3.

   What is a vertical curve primarily used for?

   • To connect two roads
   • To provide smooth transitions between grades
   • To increase speed limits

   Hint

   Think about what happens when grades change.

4. 4.

   True or False: A valley curve has upward convexity.

   • True
   • False

   Hint

   Consider the shape of both curve types.

5. 5.

   Given a roadway with grades of +2% to -1.5%, calculate the length of the vertical curve required if the rate of change is 0.05%.

   Hint

   Use the change in grade divided by the rate of change.

6. 6.

   Design a vertical curve with a gradient change from a +4% to -3% over a distance of 120 m. Find the length of the curve required.

   Hint

   Remember to calculate based on allowed changes.