Characterization and development of closed form solutions for axle load spectra associated with trucks circulating the highways of Colombia

An appropriate design of pavement structures requires estimation of the effects produced by traffi c loads. For this reason, it is necessary to predict the number of vehicles traveling on road surfaces, identifying the axle confi gurations and the magnitude of the load. Thirty-eight (38) mobile weigh stations were positioned on different strategic points of the Colombian national road network to characterize the traffi c condition of the country, 59,622 trucks were observed. This paper presents Axle Load Spectra that could be used to characterize the traffi c condition of the Colombian's highway network. Data showed that the different axle confi gurations (Single, Tandem and Tridem) exhibit two peaks, associated with loaded and unloaded truck conditions. It was noted that a signifi cant number of axles exceeds the permitted load limit, which could explain the critical state of the road network in Colombia. Finally, a mixture of three (3) theoretical distributions was used to characterize the overall axle load distributions. The proposed model presents acceptable predictive capabilities; therefore, it has potential to be used as a tool in the design process of the pavement.