EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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4 resultados
Resultados da Pesquisa
Item Resistance factor calibration for perforated cold-formed steel compression members.(2022) Jardim, Roberta Layra Faragó; Freitas, Marcílio Sousa da Rocha; Brandão, André Luis RiqueiraCold-formed Steel profiles are structural profiles widely used in civil construction. They are often manufactured with perforations. The designing can be performed using the direct resistance method. Formulations were adapted by Moen and Schafer (2008) to consider the presence of perforations in these profiles. The objective of this study is to investigate the structural safety of columns with web perforations. The calculation of the resistance capacity was performed using the formulations proposed by the authors. The reliability indexes were determined using the First Order Reliability Method (FORM), First Order Second Moment (FOSM) and Monte Carlo Method (MCM), which are reliability methods for the Load and Resistance Factor Design (LRFD) and Limit States Design (LSD) philosophies. Following the same criteria performed by AISI S100, the resistance factors were obtained from the FOSM method. Based on the results, it was found that the desired security level for the LSD philosophy was not achieved. The calculated resistance factors are predominantly lower than the target. However, for the LRFD philosophy, the safety level was achieved, and the resistance factors were higher than the target.Item Reliability assessment of cold-formed steel beams by the FORM method.(2021) Toledo, Fernanda Ferra Andrade; Freitas, Marcílio Sousa da Rocha; Brandão, André Luis RiqueiraThis article presents a procedure for the reliability assessment of cold-formed steel beams based on the Direct Strength Method (DSM) and the Effective Section Method (ESM). Using a comprehensive database, a statistical analysis of the test results was performed to determine the statistical properties of the professional factor random variable. The statistical parameters related to material strength, geometric properties and load effects were obtained from established references for reliability analysis. Safety levels compatible with the North American and the Brazilian codes relating to structural design of cold-formed steel members have been established. The first-order reliability method (FORM) was used to calculate resistance factors φ for usual nominal live-dead ratios. The results of the reliability analysis showed that the DSM and ESM design methods have similar levels of reliability. The same resistance factor as the DSM can be used for the ESM, without compromising the minimum level of reliability established. The results obtained with the LRFD calibration data, presented a good approximation with the load factor φ = 0.90, except for the distortional mode. With the LSD calibration data, values well below the specified were required in order to achieve the required level of reliability. It was also found that the load factor γ = 1.25, in the format of the Brazilian standard, could reach the safety requirements established for all buckling modes.Item Analysis of beam-to-upright end connections steel storage systems.(2020) Escanio, Lucas Alves; Elias, Guilherme Cássio; Neiva, Luiz Henrique de Almeida; Alves, Vinicius Nicchio; Sarmanho, Arlene Maria CunhaThis study presents an experimental and numerical research into the behavior of beam-to-upright end connections, which are part of steel storage systems. A total of 21 cantilever tests comprising three upright and four beam cross sections, were conducted, and a finite element numerical model was developed. The model was developed to compare its results with experimental results and to extrapolate these results in a parametric analysis. The aim of the study is to evaluate the behavior, semi-rigidity, and influence of the geometric parameters in the stiffness of beam–upright lipped connections of pallet-type industrial storage systems. The results of the numerical model showed good correlation with the experimental results, in terms of moment–rotation behavior and the initial stiffness values, with a maximum differenc e of 10%. In the parametric analysis, a pattern was observed in the variation of stiffness when the dimensions—mainly the height of beams—of the prototypes were increased.Item Ultimate load of steel storage systems uprights.(2018) Elias, Guilherme Cássio; Neiva, Luiz Henrique de Almeida; Sarmanho, Arlene Maria Cunha; Alves, Vinicius Nicchio; Castro, Ana Flávia Barbosa eThis study presents an experimental investigation into the behavior of steel storage rack perforated uprights under axial compression. A total of 44 prototypes comprising eleven cross-sections and four lengths were tested, and a buckling curve of the studied uprights is proposed. The focus of the study is to compare the ultimate loads of the experimental uprights by numerical and theoretical analysis, through modifications to the direct strength method (DSM) equations, using the Brazilian and European design codes. The theoretical values obtained are smaller than the experimental ones, and the interaction of distortional and global buckling is also discussed. The ultimate loads obtained with the proposed buckling curve were less conservative than the DSM equations.