Effects of Load Distributions and Axle and Tire Configurations on Pavement Fatigue

Damage factor relationships for axle and tire configurations are presented. Adjustment factors are provided to account for variations in load distributions within axle groups, distances between axles of a tandem, and variations in tire pressure for both dual and flotation tires. Properly accounting for accumulated fatigue of a pavement requires a traffic volume, proportions of vehicle styles (classifications) within the of service, estimate of the average damage factor for each classification, reasonable measure of traffic stream, dates and estimates of tire contact pressures. All adjustment factors presented are based on analyses of a limited number of structures and should be used with caution. The accuracy of these analyses is not in question, but the range of structures investigated was limited. They are intended to indicate the trend, shape, and sensitivity of various inter-relationships and their relative magnitudes. Modifications may have to be made upon the analyses of additional pavement structures. Kentucky traffic may differ from that in other areas, both in types of vehicles in the traffic stream and the type and direction that cargo is being transported