Development of Dynamic Analysis Techniques for Falling Weight Deflectometer Data (1175-2)

Results of computations of pavement layer properties are presented for 24 Texas asphaltic concrete (AC) pavement sections. Layer properties were computed using dynamically analyzed Falling-Weight Deflectometer (FOOD) time history data Asphaltic concrete (AC) surface layer creep compliance data lower layer moduli and subgrade sublayer thicknesses were extracted from the FWD data using a computerized back-calculation process. The Pavement Dynamic Analysis Procedure (PDAP) developed for the project is described.|All 24 sections including two pavement sections with known near-surface bedrock were successfully analyzed, giving realistic values for the AC layer creep parameters, lower layer moduli, and lower subgrade layer thickness. A graphical comparison study of pavement deflection frequency response functions is presented. The agreement for the pavements showed what appears to be severe lateral modal vibration interference in the innermost sensors at frequencies between 30 and 80 Hz.|Back-calculated layer data was compared with laboratory data from pavement samples. Laboratory creep data of AC layer samples agreed well with back-calculated data. Resonant column data on base course and subgrade moduli was used by highway engineers for pavement performance evaluation and prediction.