Developing a Network-Level Structural Capacity Index for Structural Evaluation of Pavements

The objective of this project was to develop a structural index for use in network-level pavement evaluation to facilitate the inclusion of the pavement's structural condition in pavement management applications. The primary goal of network-level pavement management is to provide the best service to the users for the available, often limited, resources. Pavement condition can be described in terms of functional and structural condition. The current widespread practice of network-level pavement evaluation is to consider only the functional pavement condition. This practice results in suggested treatments that are often under-designed or over-designed when considered in more detail at the project level. The disagreement can be reduced by considering the structural capacity of the pavements as part of a network-level decision process. This study developed a flexible pavement structural index to use for network-level pavement applications. Available pavement condition data were used to conduct a sensitivity analysis of the index, and example applications were tested. The results indicated that including the structural index developed, named the Modified Structural Index (MSI), into the network-level decision process minimized the discrepancy between network-level predictions and project-level decisions when compared to the current network-level decision-making process. A pilot implementation of the MSI showed that it can be used to support various pavement management decision processes, such as network-level structural screening, deterioration modeling, and development of structural performance measures. The pilot test also indicated that the impact of the structural condition of the pavement on the performance of a maintenance treatment and its impact on life-cycle costs can be quantified.