AXLE LOAD ON ROUNDWOOD TRUCK TRANSPORT SET IN RELATION TO LOAD, SET TYPE, SEASON AND GROSS VEHICLE WEIGHT

In round wood transport, high variability of transported assortments, made of different tree species, and variability of wood moisture content do not allow to clearly determine the weight of transported raw material.This affects the exceeding gross vehicle weight (GVW) of the transport unit above the legal limit.With significant GVW exceeding, forest roads are exposed to high tonnage vehicles, which results in vehicle axle loads above the accepted design parameters for the pavement and cause faster degradation of the forest roads.The purpose of this study was to investigate the real axle loads of roundwood transport vehicles arising from the gross vehicle weight (GVW) of the transport unit in different seasons of the year and depending on the type of transport set and the type of wood assortments.Measurements of axle loads for round wood truck transport units were carried out on the sites of three large wood industry companies from the north of Poland, which process different types of wood.The load on the individual axles of high tonnage truck units was measured using Model DINI ARGEO WWSD portable truck scales with a 3590M309 weighing terminal with 0.01 t graduation.In total, measurements were taken for 904 round wood deliveries, made by different transport units.Dominated was truck and trailer set with 473 deliveries, including 344 deliveries by six-axle sets.The second most frequently observed was truck and semi-trailer, 334 deliveries, where 193 was made by six-axle sets.There is a decrease in the use of truck and dolly and truck and lightweight semi-trailer combinations, which were five-axle combinations, for round wood deliveries.The lowest axle load for all sets occurs on axle one in the range of average values of 7.07-7.86twith a spread of results from 4.49 to 10.20t.The highest average axle loads of 9.15-12.43twere found on axle two for all observed transport sets, where a maximum value of 14.52t was also found.There were statistically significant differences in the values of loads on individual axles depending on the