Comparison of Simplified Elastostatic and Elastodynamic Models for Falling Weight Deflectometer Data Interpretation

Abstract

The characterization of pavements and subgrades by interpreting falling weight deflectometer data is discussed. Two backcalculation strategies—one based on an approximate elastostatic model and the other on dynamic impedance for a two-layered pavement subgrade system—are presented and applied to data collected along experimental pavement sections. Both strategies characterize the structural integrity of a pavement by equivalent asphalt thickness and the stiffness of the subgrade by effective subgrade modulus. It is indicated that, although both procedures predict similar trends, the values of the system parameters differ, particularly the equivalent asphalt thickness. The net pavement-subgrade stiffness predicted using dynamic impedance was found to be consistently higher than that obtained with the elastostatic model for the data studied. The capability of dynamic impedance to identify variations of in situ conditions along a section of roadway is also demonstrated.

Get full access to this article

View all access options for this article.

References

Stolle

D. F. E.

, and Jung

F. W.

. Simplified, Rational Approach to Falling Weight Deflectometer Data Interpretation. In Transportation Research Record 1355, TRB, National Research Council, Washington, D.C., 1992, pp. 82–91.

Magnuson

A. H.

, Lytton

R. L.

, and Briggs

R. C.

. Comparison of Computer Predictions and Field Data for Dynamic Analysis of Falling Weight Deflectometer Data. In Transportation Research Record 1293, TRB, National Research Council, Washington, D.C., 1991, pp. 61–71.

Ketcham

Dynamic Response Measurements and Identification Analysis of Pavement During Falling Weight Deflectometer Experiments. In Transportation Research Record 1415, TRB, National Research Council, Washington, D.C., 1994, pp. 78–87.

Stolle

D. F. E.

, and Peiravian

. Falling Weight Deflectometer Data Interpretation Using Dynamic Impedance. Canadian Journal of Civil Engineering, 1996.

Roesset

J. M.

, and Shao

. Dynamic Interpretation of Dynaflect and Falling Weight Deflectometer Tests. In Transportation Research Record 1022, TRB, National Research Council, Washington, D.C., 1985, pp. 7–16.

Chang

D.-W.

, Kang

Y. V.

, Roesset

J. M.

, and Stokoe

K. H.

II Effect of Depth to Bedrock on Deflection Basins Obtained with Dynaflect and FWD Tests. In Transportation Research Record 1355, TRB, National Research Council, Washington, D.C., 1992, pp. 8–16.

Nazarian

, and Stokoe

K. H.

II Nondestructive Evaluation of Pavements by Surface Wave Method. In Nondestructive Testing of Pavements and Backcalculation of Moduli, ASTM STP 1026 ( Bush

A. J.

III , and Baladi

G. Y.

, eds.), American Society for Testing and Materials, Philadelphia, Pa., 1989, pp. 119–137.

Stolle

D. F. E.

Analysis and Interpretation of Falling Weight Deflec-tometer Data. Report MTO Project 21230, 1992.