Question

While aligning a road with a ruling gradient of 5%, a horizontal curve of radius 60 m is encountered. The compensated gradient at the curve is

• A. 3.75%
• B. 3.5%
• C. 4%
• D. 4.25%

Answer 1

The correct option is C 4%

$\text{Grade compensation (GC\%)}=\frac{30+R}{R}>\frac{75}{R}$

$\text{GC(\%)}=\frac{30+60}{60}>\frac{75}{60}$

$\therefore \text{GC (\%)}=1.25\%$

$\text{Compensated Gradient}=\text{Ruling Gradient}-GC\left(\%\right)$
$=5-1.25$
$=3.75\%$

But the gradient need not be eased beyond 4%.

$\therefore \text{Compensated Gradient}=4\%$