Approach to determine the impact of lateral distribution of vehicles on fatigue damage in flexible pavement

The lateral distribution of vehicles results in a reduction in the intensity of damage to a pavement, which in turn affects the pavement design parameters. This study proposes a probabilistic model to incorporate the impact of the lateral distribution of wheel load on fatigue damage. The use of a continuous function for damage index determination in the proposed model allows accurate estimation over the entire pavement domain. For the truncated normal distribution of the wheel load, the fatigue damage indices were estimated for different bituminous layer thickness (75–250 mm at an increment of 25 mm), base layer thickness (400 mm and 450 mm) and subgrade layer CBR (5% and 10%). The results showed that the effect of the thickness of the bituminous layer and subgrade strength on the damage index was relatively higher than base layer thickness. In terms of prediction accuracy, the proposed model and an existing model exhibited similar results, indicating that the proposed methodology can be used for any type of pavement for the estimation of fatigue damage at different lateral positions. Also, one can incorporate any probability density function, including a truncated normal and uniform distribution, leading to flexibility among the users to represent the wheel wander suitably.