Analyses of the aasho road test results to derive load equivalency factors (lefs) as a function of pavement condition (present serviceability index (psi)) were performed. The results of the analyses show that the lefs are strongly dependent on the pavement condition, i.E., Lef values increase as the initial psi decreases. This result may affect the analyses of legal load limits and special movement ofheavy trucks. To adapt the above results to multiple loads, a framework based on limiting the strain at the top of the subgrade and various strain criteria for various psi of the pavement were developed and are presented. A modification to the common miner's law for damage accumulation was calibrated for tandem axle loads and suggested for use with multiple wheel axles. The use of the proposed framework is illustrated for single, tandem, and multiple axle loads. The results showed that the lefs of all load configurations are dependent onthe condition of the pavement. This paper appears in transportationresearch record no. 1286, Design and evaluation of rigid and flexible pavements 1990.
Abstract