What is grade of compensation ? How to calculate grade of compensation? (Example)

What is Grade compensation?

Grade compensation

Grade compensation is the reduction of the gradient whenever we need to consider the gradient along with the horizontal curve. Gradient with horizontal curve may create difficulty in driving and cause accidents.

Basically in the hilly region, grade compensation is common, because the horizontal curves are more within a shorter distance

How to calculate grade compensation?  

According to the IRC ( Indian Road Congres ), the compensated gradient should not be less than  4% after the compensation.

To calculate the grade compensation use this formula-

                                     GC = ( 30+ R ) /R  ....................(1)         where ,  R = Radius of the curve 

                                     GC = 75/R      ............................(2) 

Now take the minimum value from equations (1) & (2), and apply for the compensation on the gradient.

Examples: