análise estrutural em cobertura cônica de silo cilíndrico metálico pelo método dos elementos finitos

Abstract

In Brazil, structural failures of cylindrical steel silos have occurred more frequently than failures in other structures. These collapses may be caused by the absence of standardized recommendations, both for calculating the actions and for calculating the resistance of the structural elements of the silos. In this context, the objective of this work was to establish models to estimate the actions in conical roof of steel silos to use them in linear stability analyses, internal forces, and dimensioning. Thus, in the wind action calculation, the models to estimate the external pressure coefficients of the roof were determined with the Fourier series from the experimental data produced by Kabeli (2002). To calculate the actions of the thermometry cables, the model of Schwab et al. (1991) was established. With the SCIA Engineer software, which uses the finite element method, linear stability analyses were performed for three structures, the first without a bracing system, and the others with. The result of these analyses made it evident that the bracing systems provided greater stability to the conical roof structures. In the stability analysis, it was observed that the lowest values of the load factors were calculated for the combination of actions in which the action of the thermometry cables acted as the main variable action. The internal efforts were determined as recommended by NBR 8800 (ABNT, 2008) based on first and second order analyses. The design of the radial beams (stringers) and the polygonal beams (crossbeams) were carried out according to the recommendations of the NBR 14.762 (ABNT, 2010) standard. In these analyses, respectively, the verification factor of these elements was equal to 0.94 (94%) and 0.52 (52%).