Mechanistic-Empirical Approach to Assessing Relative Pavement Damage

Abstract

The purpose of this investigation was to examine the feasibility of using conventional pavement analysis tools to derive mechanistic-empirical load equivalency factors (LEFs) applicable to wheel assemblies and pavement cross-sections not included in the AASHTO guide tables in a manner that would provide seamless continuity with current pavement engineering practices. The derivation of such LEFs was pursued on the assumption that two controversial concepts—namely, load equivalency and linear damage accumulation—were, in fact, valid. The purpose of this assumption is to investigate whether it is possible to reach reasonable conclusions for as long as no theoretically valid alternatives to these concepts are available. It was found that it is possible to reproduce with a reasonable fit the statistical/empirical LEFs found in the AASHTO guide tables, using layered elastic analysis and the fatigue relationship derived by Vesic and Saxena. Other conventional fatigue relationships yield unreliable results when compared to the AASHTO LEFs. It is also possible to derive mechanistic-empirical extensions to the AASHTO LEFs using this approach, so tire configurations and pavement cross-sections not included in the AASHTO tables of LEFs can be accommodated in a seamless and equitable manner.