Axle-load estimation without weigh-in-motion survey

Abstract

Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.

Modern road pavement design requires the knowledge of axle loads. These are usually obtained by means of Weigh-In-Motion (WIM) measurements. The WIM technology is complicated and measurements are expensive. However, reasonably good estimates of the axle-load distribution can be obtained by a method combining the current knowledge of road and traffic with the WIM information obtained in the past. The method estimates the distribution of axle loads that is likely to occur on a route with a certain type of axle-load distribution, with a certain split of short, medium and long heavy vehicles, and under certain intensity of law enforcement against overloading. The estimation method, called ALDIS, was derived from a comparison of WIM records obtained under condition of no law enforcement and strong law enforcement, and from an analysis of good-quality WIM measurements done on 22 permanent sites in 2012. The axle-load distribution produced by the ALDIS method can be used in mechanistic pavement design tools such as cncPAVE, or Cyrano, to arrive at practical and economic pavement configuration.