Influência da geometria de tremonhas concêntricas e excêntricas nos esforços de silos esbeltos metálicos

Abstract

The slender vertical silos are storage structures whose stresses and deformations in the concentric and eccentric hoppers still require studies for their complete knowledge, as there is great variability in the pressures due to the stored product or the structure geometry. The objective of this scientific, technical and applied work was to evaluate the pressures exerted by the storage of maize on the walls of different hopper geometries, in addition to the tensile efforts in the devices that connect these to the pilot silo wall and the axial efforts in its pillars. Therefore, it was proposed to analyze the structural behavior of hoppers installed in a pilot silo, whose design is based on the principle of models by Pieper and Schütz (1980), bases as a standard by the German standard DIN 1055-6 (2000). These hoppers were evaluated when subjected to static and dynamic loads (filling, storage and discharging) of maize kernels. From these pressure results, they were compared with the theories of Janssen (1895) and Walker (1966) and with the main international standards for the calculation of slender silos (ISO 11697:2012, EN 1991-4:2006 and AS 3774:1996 ). The results showed that the normal pressures in the hoppers are dependent on their geometry, with great variation of these efforts with the eccentricity of the discharge mouth, with the inclination of its walls, with the geometry of the silo wall (in this work, walls were studied smooth and wavy) or with the condition of filling or discharging the silo. These same variables, objects of this study, showed great influence on the traction efforts in the devices that support the hoppers in the silo and in the vertical loads that are transmitted to the columns. This information is important because the international standards do not deal with loads caused by large eccentricity hoppers and are necessary for the design and development of equipment and silos aiming at the safe and economical handling of the product, aiming at the integrity of the structure and equipment during the processing of stored products.