Avaliação da aplicação da norma ACI-313:1997 no dimensionamento de silos multicelulares elevados de concreto armado para café

Abstract

The storage of bulk solids is done in silos used in industry, agriculture, iron metallurgy and ports and others. These can be built with the most different materials such as reinforced concrete, steel, wood, armed mortar, etc. At present, there is a worldwide trend of designing structural projects, adopting the criterion of dimensioning in the limit states with the purpose of performing safe and economical projects. So, a more accurate determination of the actions acting on the structures of silos becomes necessary. In this work, it was aimed to establish a proposal of structural project of coffee storage with relation to the already existing traditional methods. A design with different hypothesis of full and empty cells was developed in order to contemplate the storage in bulk, motion and transport of the product. The model of building construction was vertical and elevated reinforced concrete multicellular silo. The silo have cells to store 1,500 bags. It was projected on the basis of the ACI 313:1997 code, considering the wedge- type hopper. The structural project was divided in steps: determination of the physical properties of coffee, determination of the hopper geometry, geometric design, calculation of the actions on the structure and silo design. On the basis of the results, the areas of horizontal armor for the wall of the side “a” and “L” of the silo and of the hopper were determined aiming to meet the dimensioning criteria in a safe and economical manner on the basis of ACI 313:1997 code. Considering the transition of the silo wall to the hopper, a critical point in the elevated silos, it follows that the verification generated an increase of pressure in the calculations of 60% and 59% in the silo walls “a” e “L” and 44% e 43% in the “a” and “L” of the hopper sides for the additional pressure by the no DIN 1055-6:2005.