engleski

Comparison of Real Axle Loads and Wheel Pressure of Truck Units for Wood Transportation with Legal Restrictions

In Croatian Forestry wood transportation is usually carried out by trucks with trailer (forest truck unit) and trucks with two-axle semitrailer (forest semitrailer unit). As they travel on public roads, they are subject to severe legal restrictions defined by the “Regulation on Technical Conditions of Vehicles in Road Traffic” - (Official Gazette “Narodne novine”, No. 51/10). Based on the analysis of the said Regulation, it can be concluded that all restrictions are set on allowable loads of axles and total mass of the vehicle. At the same time axles of trucks and trailers are equipped with dual tires to decrease wheel pressure on road surface. The aim of this research is to determine axle loads of the truck with trailer and truck with semitrailer during transportation of different types of loads (type of wood assortments, species of wood, wood moisture and way of piling wood assortments in the truck load space) as well as to determine contact pressure of truck and trailer/semitrailer wheels. The research was performed on the Scania truck with trailer, Iveco Trakker 440 with trailer and MAN truck with semitrailer. The axle loads were measured by a portable measuring platform and scales. Different mathematical models based on tire characteristics (dimensions, inflation pressure) were used for the calculation of wheel contact area. Wheel pressure was determined based on measured wheel load and calculated contact area. By comparing the results with the legal restrictions of the Regulation, analysis could be made of the right way of setting restrictions of timber transportation by trucks with trailers or semitrailers, which would reduce wheel pressure on road surface and, in a longer period, reduce maintenance costs of forest roads as well as increase the life cycle of technical equipment.

axle load; wheel pressure; truck with trailer; truck with semitrailer; regulations

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