A Risk-Based Prioritization and Optimization of Pavement Overlay Thickness

In the reliability method, design is done based on the level of reliability proposed in the regulations. ‎Design is done according to the current condition of the pavement and the amount of repair in ‎subsequent periods doesn't attention to these methods. A method for repairing the pavement is ‎proposed in this study, which in addition to the current situation, consequences of its failure and ‎reconstruction attention. Risk analysis methods were used due to consider these consequences and the ‎costs of the next period of repair in the future were estimated according to the amount of current ‎pavement repair and the inflation rate. The total cost of pavement repair is equal to the sum of current ‎and future costs. The amount of repair at the lowest total cost is obtained by optimizing, which is equal ‎to the amount of optimal pavement repair. To compare the two methods, traffic data and pavement ‎condition of the Qom-Salafchegan route were collected and the most appropriate probability ‎distribution of variables was determined by the Anderson‏-‏Darling test. The pavement was designed ‎with a higher level of reliability in the proposed method according to the results. Also, the total cost of ‎pavement repair in the proposed method is less than the reliability method, thus it is more economical ‎and decreases costs. Then, pavement sections were prioritized using risk analysis methods and ‎considering variability in variables. The present study prioritizes the pavement section according to the ‎amount of reduction in the probability of failure and the risk of the whole route per toman spent on ‎repair. The results of this method allow decision-makers to predict current and future costs of repairs ‎and to plan more accurately for the maintenance and repair budget. ‎