👉Road Super Elevation

💫Super elevation is the tilting of the road surface at a curve so that the outer edge of the pavement is raised above the inner edge.

⏺It helps counteract the effect of centrifugal force on vehicles moving along curved paths.

⭐️Purpose of Super Elevation

❇️To reduce the tendency of vehicles to overturn or skid outward.

❇️To provide comfort and safety to drivers.

❇️To allow vehicles to negotiate curves at higher speeds smoothly.

⚙️ Formula

🔰e + f = V2/127R

🎲Where:

⏺e = rate of super elevation (m/m)

⏺f = lateral friction factor (usually 0.15)

⏺v = speed of vehicle (km/hr)

⏺R = radius of curve (m)

📏 Design Steps

1. Calculate required super elevation using the above formula.

2. Limit the maximum super elevation (generally 1 in 15 to 1 in 20, or 7% for highways).

3. Provide transition length for smooth rise.

🛣️ Methods of Providing Super Elevation

⏹By rotating the pavement about the inner edge.

⏹By raising the outer edge with respect to the center.

⏹By rotating about the center line (commonly used method).

⚠️ Limitations

⚡️Not suitable for urban roads with slow-moving traffic.

⚡️Excessive super elevation can cause problems for slow or parked vehicles.

📍Advantages

⏺Increases vehicle stability.

⏺Reduces side friction demand.

⏺Enhances comfort and safety at curves.

@etconp