2.44. Establish the formulae to calculate various elements to set out the compound curve.

Try these first

1. 1.

   Define a compound curve.

   Hint

   Think about what you learned regarding curves in road design.

2. 2.

   What is the formula for calculating the average radius of a compound curve?

   Hint

   Consider how you average two numbers.

3. 3.

   What is a compound curve?

   • A single circular arc
   • Two or more circular arcs connected
   • Only straight paths

   Hint

   Think about how roads transition.

4. 4.

   True or False: The length of a compound curve is proportional to the deflection angle.

   • True
   • False

   Hint

   Higher deflection means a longer curve.

5. 5.

   Calculate the external distance for a compound curve made with R1 = 300 m and R2 = 450 m if the deflection angle is 60°.

   Hint

   Remember to divide the deflection angle when calculating.

6. 6.

   A road section's compound curve has radii of 250 m and 350 m, respectively. Calculate the total length of the curve for a deflection angle of 75°.

   Hint

   Use the length formula and stay mindful about degrees to radians.