The process involves using data obtained from Falling Weight Deflectometer (FWD) testing to estimate a numerical index representing the overall load-carrying capacity of a pavement structure. The FWD applies a controlled impulse load to the pavement surface, and sensors measure the resulting deflections at various distances from the load. These deflection measurements are then used in backcalculation procedures to estimate the elastic moduli of the pavement layers. The structural number is ultimately derived from these moduli and layer thicknesses.
This evaluation method is critical for pavement management and rehabilitation planning. Accurate assessment of structural capacity allows engineers to identify pavement sections that are structurally deficient and prioritize maintenance or rehabilitation efforts. This approach provides a non-destructive alternative to destructive testing methods, reducing disruption to traffic flow. Historically, this evaluation process has enabled informed decisions regarding resource allocation, extending pavement service life, and optimizing investment in infrastructure.
