SEASONAL LOAD LIMIT DETERMINED BY THE CRITERION OF UNIFORM FAILURE RATE.

Efficient performance of the highway system requires rational optimization of its use within the constraints of the adopted strategy. During the spring-thaw season in the northern part of the United States many highway agencies reduce the maximum load limits on some roads in an attempt to preserve the pavement serviceability. The method considers various types of pavement failure such as fatigue cracking, rutting, and roughness and combines them by using the AASHO serviceability index. If the properties of the pavement materials are determined, mechanistic approaches can be used to predict the failure trend and to adjust the axle load limit to maintain the uniformity of this trend. A computer program LOADLMT has been developed in order to determine the optimum seasonal axle load limit on flexible pavements under various conditions. The use of the method was verified on a typical road under typical traffic distribution, material properties, and environmental conditions.