Pavement Analysis Group (PAG)
The mission of the PAG is to develop state of the art models and procedures to be used in the condition assessment of pavements. The PAG deals primarily with the analysis of nondestructive test results obtained from the field via the Falling Weight Deflectometer (FWD) using various advanced material models, finite element analysis, and system identification techniques. The FWD applies dynamic loads to pavement structures by dropping a pre-described weight from a specified height. Pavement response to this load is measured through the use of geophones, which measure pavement deflections at standard distances from the load center. These measured deflections are matched with deflections computed for the specific pavement structure using theoretical/numerical methods and assumed materials properties. The best match between the measured deflections and the computed deflections is found using system identification techniques, such as artificial neural networks. Currently, the PAG is developing a simple, practical deflection interpretation procedure for condition assessment of distressed pavement layers and a method for estimating subgrade modulus under rubblized PCC slabs using the deflections measured from intact PCC slabs before the rubblization. Both field data and synthetic data generated from the finite element analysis are used in developing these algorithms that account for the dynamic nature of FWD loading and nonlinearities of unbound layer materials.
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