9.1. Two straights AC and CB

Try these first

1. 1.

   Define chainage and give an example.

   Hint

   Think of how distances are marked on a road.

2. 2.

   What is the formula for calculating tangent length?

   Hint

   Identify R and Δ in a simple example first.

3. 3.

   What is the formula for calculating the tangent length in circular curves?

   • Length = R Δ
   • Length = R tan(Δ / 2)
   • Length = R² Δ(π/180)

   Hint

   Pay attention to how the angle is used in calculations.

4. 4.

   True or False: Chainage can only represent straight line distances.

   • True
   • False

   Hint

   Think back to how chainages are established on curves.

5. 5.

   Given two straights with a meeting point at a chainage of 1500m and a deflection angle of 45°, calculate the required radius for a designed curve and report the tangent lengths as well.

   Hint

   Apply both formulas sequentially for clarity.

6. 6.

   A circular curve needs to connect a point of intersection at 2000m. If the radius is set to 100m and the deflection is 90°, calculate both your tangent lengths and the overall chainage for endpoints.

   Hint

   Map your solutions stepwise and ensure units are consistent.