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GATE 2020 CE (CE2) – Question 30

Highway Pavements · Design of flexible and rigid pavements · 1 mark · Numerical answer

Find vehicle damage factor for a 15 tonne axle relative to a standard 8 tonne axle, to two decimals.

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Correct answer: 12.3 to 12.4

Explanation

The vehicle damage factor (VDF) compares an axle load with the standard axle through the fourth-power law:

$\text{VDF}=\left(\dfrac{\text{axle load}}{\text{standard axle load}}\right)^4$.

Here $\text{VDF}=(15/8)^4=1.875^4$. Since $1.875^2=3.515625$ and $3.515625^2=12.3596$, the VDF to two decimals is **12.36**.