BACK CALCULATION OF PAVEMENT LAYER MODULI USING A NONLINEAR OPTIMIZATION TECHNIQUE

Falling Weight Deflectometer (FWD) testing is used for nondestructive structural evaluation of existing pavements. The deflection data from FWD can be used for estimation of layer moduli by an iterative technique. In the calculation process, commonly known as "backcalculation", comparison is made between calculated deflections from a suitable theory and those measured by the FWD. The estimated moduli values correspond to the best fit of the measured deflection basin. In this study, a nonlinear optimization technique for solving constrained objective functions has been used to estimate the layer moduli in the backcalculation process. The backcalculation scheme developed in this study is applied to 3- to 6-layer pavements. The method was verified by simulated deflection data from elastic layer theory and FWD deflection measurements on 13 in-service pavements in Arizona, and found to approximate closely the results of the manual approach of matching deflection basins. The method yields more rational results than an existing method of back calculation. The algorithm has been coded in a computer program called Arizona Deflection Analysis Method (ADAM).

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 61-76
  • Serial:
    • Volume: 1

Subject/Index Terms

Filing Info

  • Accession Number: 00728633
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Nov 27 1996 12:00AM