Vehicle Damage Factor (VDF) in IRC: 31-102

The Vehicle Damage Factor (VDF) is an important concept in the field of civil engineering, specifically in the design and analysis of pavements and roads. It is defined in the Indian Road Congress (IRC) publication number 31-102, which provides guidelines for the design of flexible pavements.

Definition and Purpose of VDF

The VDF, as per IRC: 31-102, is a multiplier used to convert the number of commercial vehicles with different axle loads and axle configurations into the number of repetitions of a standard axle load magnitude. It is used to estimate the damage caused by commercial vehicles to pavement structures.

Options and Correct Answer

The given question provides four options for the magnitude of the standard axle load. Let's evaluate each option to determine the correct answer:

a) 30 kN
b) 65 kN
c) 75 kN
d) 80 kN

Among these options, the correct answer is option 'D', which represents a standard axle load magnitude of 80 kN.

Explanation of the Correct Answer

The correct answer can be determined by understanding the purpose of the VDF. The VDF is used to convert the number of commercial vehicles with varying axle loads and axle configurations into an equivalent number of repetitions of a standard axle load. This standard axle load represents the damage potential of a single axle load on the pavement.

In order to estimate the damage caused by commercial vehicles accurately, it is essential to select an appropriate standard axle load magnitude. The magnitude should be chosen based on the characteristics of the commercial vehicles commonly using the road network under consideration.

In the given question, option 'D' with a magnitude of 80 kN is the correct answer. This implies that the VDF provided in IRC: 31-102 is specifically calibrated for commercial vehicles with an axle load magnitude of 80 kN. This magnitude is likely to be representative of the axle loads commonly observed in the region or country where the guidelines are applicable.

By using the VDF and multiplying the number of commercial vehicles with their respective axle loads and configurations by the standard axle load magnitude, an estimate of the damage caused by commercial vehicles can be obtained. This estimate is crucial in the design and maintenance of pavements to ensure their longevity and safety.

Conclusion

In summary, the Vehicle Damage Factor (VDF) in IRC: 31-102 is a multiplier used to convert the number of commercial vehicles with different axle loads and axle configurations into the number of repetitions of a standard axle load magnitude. The correct answer for the magnitude of the standard axle load in the given question is option 'D' with a magnitude of 80 kN.