Análise de tensões em silos circulares metálicos de baixa relação altura/diâmetro

Abstract

With the current records of agricultural production, the great deficit of storage capacity is on the agenda in the national scenario. The lack of silos shows the importance of developing research in this area. As Brazil does not have a regulatory standard, manufacturers use international norms, nor do they use them. The objective of this work was to compare the lateral, friction and vertical stresses in circular metal silos of low height/diameter ratio. The properties of corn and soybeans produced in the state of São Paulo were used in this study, and they were obtained in the literature. For this comparison, the European standards EN 1991-4: 2006, ISO 11697: 1995 and Australian AS 3774-1996, based on the theory of Janssen (1895), were used to find static tensions. For dynamic unloading activities, the standards use overpressure coefficients. Horizontal and friction pressures were higher for soybean compared to maize values, different from vertical what happened with vertical pressure. The values of horizontal pressure and friction obtained by the methods of standards EN 1991-4: 2006 and ISO 11697: 1995 were higher than those obtained according to AS 3774-1996. For the vertical pressure, in general, the values reached through ISO 11697: 1995 were higher than those found in accordance with EN 1991-4: 2006. At the moment of discharge, the pressures according to EN standard have not changed. For ISO, vertical pressure increased by 35% compared to its static mode. For the Australian standard, the horizontal and friction pressures increased by 20%.