What are the basic requirements of road alignment? What do you mean by superelevation? How it is different from camber? Write down the significance of the superelevation?

 QN. What are the basic requirements of road alignment? What do you mean by superelevation? How it is different from camber? Write down the significance of the superelevation?

Solution:

               Alignment of the road is defined as the planed centerline of the road where the road will be constructed.

Requirement of Road Alignments

• ·          As possible as road alignment should be straight
• ·       Should be short
• ·       Should be economical
• ·       Road alignment should balance the cut and fill
• ·       It should not passe through the swampy area and populated area

Superelevation:

Superelevation is the raised portion of the outer edge of the road on the horizontal curve with respect to inner edge.

e+f= v2/127R

For Mixed Traffic,

e= V2/225R

Camber

Camber is the raised portion of the center of road for the drainage purpose

Types

1.       Straight Camber

2.       Parabolic camber

3.       Composite camber

So, Camber is used for the drainage purpose and superelevation is used to overcome the centrifugal force on horizontal curve.

Significance of superelevation

1. v   It is provided to overcome the centrifugal force on the horizontal curve of road.
2. v    Sometimes it is used as a drainage purpose at horizontal curve.
3. v   Extra-widening is provided to the curve for comfort of driver to turn the vehicle.

Finally,

                Superelevation and camber are very important component of the road. So, proper design is required to protect the road layer and reduce the road accident at horizontal curve of the road.