Some useful guidelines on super elevation design for road


In this construction video tutorial, you will learn the process for creating the design of super elevation.

While journeying in a car, the vehicle generates an external force that is called skidding. To get rid of skidding, an additional elevation is arranged to the highway i.e. road and this additional elevation is called super elevation. It is also called as cant or banking.

Alternatively, super elevation means the internal transverse inclination arranged to the cross-section the carriage way at horizontal curved section of a road.

Super elevation on road curve is essential to maintain protection against skidding and over turning caused by fast moving traffic.

Super elevation is demonstrated as the proportion of elevation of exterior edge over the inner edge to the horizontal width of the carriage way or like the tangent of the angle of slope of the road surface.

Purposes of arranging super elevation

To withstand the impact of centrifugal force operating on the moving vehicle to draw the same exterior on a horizontal curve.

To allow a fast moving vehicle to assign a curved path devoid of overturning & skidding.

To maintain the security of the fast moving vehicle.

To resist harmful impact on the road surface because of allocation of load inappropriately.

Benefits of arranging super elevation:-

It facilitates fast running of vehicles on a curved path or a straight path devoid of any risk of overturning and thus leads to elevated traffic volume.

It also facilitates to retain the vehicle to its exact position on the pavement and thus resists clash of the vehicles going in opposite direction on a curved segment of the road.

It arranges drainage of the entire width of the road approaching the inner side. So, it is not required to arrange the side drain on the exterior of the road.

The following formula is used for super elevation:-

e + F = V2 / 127 R

Here, e denotes super elevation

F denotes friction factor

V denotes velocity of vehicle

R denotes radius of curve

But, the above formula will be applicable when all the values for given.

The real design consideration for super elevation will represent with the following formula:-

e = V2 / 225R

Here, e = super elevation of the road

V = specific velocity via which the vehicle is travelling.

R = radius of the car to be determined.

To learn the complete calculation process, go through the following video tutorial.

Video Courtesy : Short Notes

Super Elevation