Monday, 25 September 2017

Classification of Gradient - Civil Engineering .Ruling,limiting,exceptional,minimum,average,floating gradient

Gradient are divided into the following categories

1.Ruling gradient
2.Limiting gradient
3.Exceptional gradient
4.Minimum gradient
5.Average gradient
6.Floating gradient

1.Ruling gradient:- The gradient usually adopted while making the road alignment is called ruling gradient.It is the maximum gradient within which the designer attempts to design the vertical profile of a road. It is also known as design gradient

2.Limiting gradient:- The gradient steeper than the ruling gradient ,which may be used for a limited Road length, is called limiting gradient or maximum gradient.It is used where the topography of place compels adopting steeper gradient than ruling gradient to minimize the cost of road construction.

3.Exceptional gradient:- The gradient steeper than the limiting gradient which may be used in short length of road, only in extraordinary situation is called exponential gradient.This type of gradient is adopted only in very difficult situation and for a short length not exceeding 100 m at a stretch.

4.Minimum gradient:- The minimum desirable slope essential for effective drainage of rain water from the road surface is called minimum gradient.Desirable minimum gradient for this purpose is 0.5 % if the side drains are lined and 1 % if the side drains are unlined.

5.Average gradient:- It is the ratio of total rise or fall to the horizontal distance between any two points along the alignment of road.

6.Floating gradient:- The gradient on which a motor vehicle moving with a constant speed continues descend with the same speed without any application of power brakes is called floating gradient.