Heavy vehicle classification and calculation rates of increasing in axle loads within the Baghdad city

In recent years, there has been a significant increase in the movement of imports and exports of goods and materials to and from Iraq, as well as between cities within the country. This increase is attributed to population growth and the expansion of construction and building projects, particularly in the completion of residential developments. Consequently, there has been a rise in the number of heavy vehicles and overloaded. It is essential to reconsider the calculation of loads as this is a critical aspect of pavement design. The objective of this paper is to Classification heavy vehicles according to the Federal Highway Administration (FHWA) that will pass through Baghdad, and accurately calculate their weights for each axle to show how the loads are distributed and determine the frequency of each load and thus understand the percentage of axles with weights exceeding the Iraqi standard limits. Take this into account when calculating the equivalent single loads and designing the pavement. This study provides a modern and realistic analysis of the current loads entering the city of Baghdad. The survey was conducted at the Al-Khalis_Azim station, as well as at the Al-Dora silo, where heavy vehicles were monitored and the weights for each axis were recorded over a month. During the month, there were a total of 1073 heavy vehicles of various types. it was determined that the highest number of passing trucks belonged to class 10, 11, and 13, which have six axles, accounting for 30% of the total, while the lowest percentage was 6% for class 5, which only includes two axles. The data collected from trucks counting and classification shows that 6% of the vehicles were classified as class 5, 23% as class 6 and 8,20% as class 7 and 8, 21% as class 9 and 11, and the highest percentage, 30%, was for classes 10, 12, and 13. It was observed that classes 9, 10, 11, 12, and 13 vehicles had dual axles (tandem), meaning that their rear axles contained more than one wheel. This setup increased the area for shedding loads, resulting in decreased pressure on the pavement. These types of trucks were more common than those with individual axles. trucks with triple axles were not considered significant due to their lower numbers compared to other vehicles.