Question

A four-lane divided highway, with each carriageway being 7.0 m wide, is to be constructed in a zone of high rainfall. In this stretch, the highway has a longitudinal slope of 3% and is provided a camber of 2%. What is the hydraulic gradient on this highway in this stretch?
1. 3.0%
2. 3.6%
3. 4.5%
4. 4.0%

Answer 1

Correct Answer - Option 1 : 3.0%

Explanation:

(i) camber is the traverse slope provided to the road

(ii) Gradient is the slope provided to the surface of the road in the longitudinal direction for vertical alignment.

hence hydraulic gradient = longitudinal slope = 3%

Camber to be provided for different types of pavement are as follows:

Type of pavement	Heavy Rain	Light Rain
Cement Concrete and high type bituminous surface	1 in 50	1 in 60
Thin Bituminous surface	1 in 40	1 in 50
WBM, gravel pavement	1 in 33	1 in 40
Earthen roads	1 in 25	1 in 33