Backcalculation of pavement layer elastic modulus and thickness with measurement errors

Abstract

This paper presents a backcalculation method for pavement layer elastic modulus and thickness. The effect of deflection measurement errors on the backcalculated results is also considered. The falling weight deflectometer (FWD) data are generated by applying a load to the pavement while calculating deflection at various fixed distances from the load centre. The measurement errors in FWD data are simulated by perturbing the theoretical deflections. Using these data, a backcalculation technique based on the improved genetic algorithm is proposed. In order to deal with the measurement errors, besides the common root mean square, a new objective function called area value with correction factor is introduced to the backcalculation algorithm. Numerical examples for two- and four-layer pavement structures are presented, which show the capability of the proposed method in backcalculation of pavement layer modulus and thickness.

Keywords::

• deflection measurement error
• area value with correction factor
• backcalculation
• pavement layer modulus and thickness
• improved genetic algorithm

Acknowledgements

This work is sponsored by FHWA/ODOT under contract number 134481. The authors are also grateful for the valuable comments from Patrick Bierl, Aric Morse, Adam Au and the assistance from Yanfei Zhao and Amirhossein Molavi Tabrizi. The authors have also benefited from the constructive comments by the three reviewers.

Notes

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