Question

A highway designed for 80 km/h speed has a horizontal curve section with radius 250 m. If the design lateral friction is assumed to develop fully, the required super elevation is

• A. 0.02
• B. 0.05
• C. 0.07
• D. 0.09

Hint:

For a horizontal curve, the super elevation can be calculated using the formula \( e = \frac{v^2}{gR} \), where \( v \) is the speed in m/s, \( g \) is the gravitational constant, and \( R \) is the radius of the curve.

Answer 1

The Correct Option is B

To find the required super elevation, we use the following formula for super elevation \( e \): \[ e = \frac{v^2}{gR} \] Where:
- \( v \) is the speed in m/s,
- \( g \) is the acceleration due to gravity (9.81 m/s\(^2\)),
- \( R \) is the radius of the curve.
First, convert the speed from km/h to m/s: \[ v = 80 \, \text{km/h} = \frac{80 \times 1000}{3600} = 22.22 \, \text{m/s} \] Now, substitute the values into the equation: \[ e = \frac{(22.22)^2}{9.81 \times 250} = 0.05 \] Thus, the required super elevation is 0.05, which corresponds to option (B).
Final Answer: (B) 0.05