Influência da irregularidade longitudinal de pavimentos na perda de carga no transporte de soja e nos demais custos operacionais

Abstract

Brazil is one of the world's largest producers of grains, but its main producing regions are far from ports and consumer centers. This generates a high demand for transportation, supplied mostly by the use of commercial motor vehicle. During the displacements, part of the product ends up being lost due to its fall through unsealed places in the bodywork, in quantity influenced by the vibration level suffered by the cargo, related to the condition of the road surface. In this sense, it is common to establish between shippers and carriers a loss limit considered acceptable. However, there are few studies that try to quantify the real loss of grains during transportation. In general, in those that do, there is no determination of any quantification and qualification parameter of the functional condition of the road, such as the pavement roughness, which can affect the loss rate. Thus, this research aimed to evaluate the influence of pavement roughness on cargo loss during bulk grain transportation and the resulting financial impacts. To this end, the soybean loss of trucks on different road segments was measured, and the pavement roughness on these same routes was determined. The data was analyzed and compared among themselves and a correlation between them was obtained. The established model relates the pavement roughness level with the relative grain loss every 100 km and presented a good statistical fit, with an R² of 0.95. The correlation was employed in evaluations, aiming to determine the impact generated by grain loss at different levels of pavement roughness. For this, the amount of soybean transported by trucks on the main route for its flow in Rio Grande do Sul was estimated and, with the IRI of the route and the established correlation, the corresponding soybean losses were calculated in product quantity and financial value, with an estimated loss of 15.48 thousand tons of soybean on this route in 2021, corresponding to R$ 47.73 million. Losses were also estimated for hypothetical scenarios of different pavement’s functional qualities on this same route, which indicated that the maintenance of the road with IRI of 1.8 m/km could generate a reduction of 5.8 thousand tons in losses, equivalent to R$ 17.95 million. To evaluate the long-term impact, the HDM-4 was used, applied to the same road route and with the models for pavement roughness progression and fuel consumption calibrated. Four maintenance scenarios were considered and vehicle operating costs were added to the analysis. It was found that the road user’s costs increased by 3,4% in relation to vehicle operating costs when considering the loss of soybeans in the evaluations. Also, that the costs with interventions over the analysis period are approximately half of the value of soybeans lost along the way in the same period and that maintaining the irregularity at lower levels (between 1.8 m/km and 2.7 m/km) throughout the analysis period leads to lower costs for users.