This paper presents a methodology for optimization of beam-column connections of plane steel frames. The objective is to obtain beam-column connections mechanically more efficient and with minimum cost by determination of the optimal dimensions for the components of the connection; satisfying mechanical constraints associated with the bending moment and the rotational stiffness of the connection, without compromising its safety and integrity. Minimum and maximum limits of geometric parameters are considered, according to current regulations. Algorithms were developed to calculate the bending moment and the rotational stiffness of the connection using the "Method of Components" of Eurocode 3. Initially, it was developed a digital database with structural profiles, steel plates and commercial bolts obtained from catalogs of manufacturers, with automatic access of the data by the computational modules of structural analysis and optimization. In the optimization model, it is adopted the connection with extended end plate without stiffeners, the design variables are the dimensions and the thickness of the end plate, the diameter and the location of the bolts. In the optimization process, we use genetic algorithms with continuous and discrete variables, with the discrete variables being associated to the database. In this way, this paper presents a computational tool fully developed in MATLAB® environment for analysis and optimal design of beam-column connections for plane steel frames. Applications that show quite satisfactory results when compared with results available in the literature are presented.

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Otimização geométrica de treliças planas utilizadas em coberturas metálicas Otimização geométrica de treliças planas utilizadas em coberturas metálicas Geometric optimization of planar trusses used in metal roofings

Assessment of tubular steel joints under bending forces Resumo Os perfis tubulares sem costura são largamente utilizados em diversos países, apesar do seu emprego no Brasil ter começado a crescer somente nos últimos anos. Considerando esse aumento, este trabalho apresenta uma análise de ligações tipo "T" com perfis tubulares quadrados (SHS) efetuada com base no Eurocode 3, no CIDECT, na NBR 16239 e na ISO 14346. Esta análise baseia-se em um modelo de elementos finitos desenvolvido no programa Ansys, que considera as não linearidades física/geométrica e do material, por meio da formulação Lagrangeana atualizada e pelo critério de escoamento de von Mises, respectivamente. São avaliados os modos de falha e as distribuições de tensões, sendo observado que os momentos resistentes obtidos numericamente são maiores que os obtidos pelas equações de dimensionamento. Um estudo para fatores de correção das equações de dimensionamento é por fim proposto.

This paper presents a methodology for optimization of beam-column connections of plane steel frames. The objective is to obtain beam-column connections mechanically more efficient and with minimum cost by determination of the optimal dimensions for the components of the connection; satisfying mechanical constraints associated with the bending moment and the rotational stiffness of the connection, without compromising its safety and integrity. Minimum and maximum limits of geometric parameters are considered, according to current regulations. Algorithms were developed to calculate the bending moment and the rotational stiffness of the connection using the "Method of Components" of Eurocode 3. Initially, it was developed a digital database with structural profiles, steel plates and commercial bolts obtained from catalogs of manufacturers, with automatic access of the data by the computational modules of structural analysis and optimization. In the optimization model, it is adopted the connection with extended end plate without stiffeners, the design variables are the dimensions and the thickness of the end plate, the diameter and the location of the bolts. In the optimization process, we use genetic algorithms with continuous and discrete variables, with the discrete variables being associated to the database. In this way, this paper presents a computational tool fully developed in MATLAB® environment for analysis and optimal design of beam-column connections for plane steel frames. Applications that show quite satisfactory results when compared with results available in the literature are presented.