The main object of providing a camber is to make the road surface durable, impervious and to

drain off rain water from the road surface, as quickly as possible. The slope of the line joining the

crown and edge of the road surface is known as camber or cross slope or cross fall. The camber on

straight roads is usually provided by raising the centre of the carriage way with respect to edges

forming a highest point on the centre line called crown.

A camber consisting of a continuous curve either parabolic or elliptical is known as barrel

camber. This type of camber is preferred by fast moving vehicles as they have to frequently cross the

crown line during overtaking operation on a two lane highway.

A camber consisting of two straight slopes joining at the centre, is called sloped camber.

Sometimes, a composite or combined camber consisting of two straight slopes with a parabolic crown

in the centre, is preferred.

The required camber of a road surface depends upon the type of road surface and the amount

of rainfall. A flat camber of 1.7 to 2% is sufficient on relatively impervious road surface like cement

concrete or bituminous concrete. In pervious surface like water bound mecadam or earth road which

may allow surface water to get into the sub grade soil, steeper camber is required. The steeper

cambers are also provided in areas of heavy rainfall. Too steep camber is not desirable.

Post a Comment