With the advancement technology for reinforced concrete structures, it becomes increasingly feasi... more With the advancement technology for reinforced concrete structures, it becomes increasingly feasible to use this technology for steel structures. The objective of this work is to present the formulation of the optimization problem of steel beams with external pretension with straight or polygonal tracing cables, considering the environmental and economic impacts. For the objective function formulation, the minimization of CO2 emission and cost in the design of the structure was considered. As constraints were established the states limits imposed by ABNT NBR 8800:2008. The program was developed within the MATLAB Platform (2016) and the optimization problem solution was obtained through the native Genetic Algorithms method. Routine validation was performed using examples found in the literature and an analysis of the predominant collapse modes was performed. The results indicate that monosymmetric profiles have gains when it comes to reducing CO2 emissions and cost when compared to d...
The literature has well established prestressing in concrete beams and its calculation procedures... more The literature has well established prestressing in concrete beams and its calculation procedures. However, its use in composite steel-concrete beams has increased despite main normative codes lacking a specific approach for it. Designers must, in most cases, combine the available criteria to calculate the standards of steel and reinforced concrete structures. This study aimed to formulate this optimization problem and analyze CO2 emissions for the optimal design of composite steel-concrete beams with external prestressing. The design variables for the optimization problem include cross-section of laminated or welded profiles, slab height, characteristic strength of concrete to compression, and number of tendons. We obtained a solution for the optimization problem via a genetic algorithm (GA) and a particle swarm optimization one (PSO). Comparative analysis with experimental example and with optimization problem of prestressed steel beam are performed. An parametric analysis to seve...
Revista Interdisciplinar de Pesquisa em Engenharia - RIPE, Jan 25, 2017
Abstract. Vigas de aco celulares sao fabricadas de perfis laminados com aberturas circulares padr... more Abstract. Vigas de aco celulares sao fabricadas de perfis laminados com aberturas circulares padronizadas e foram criadas devido a diferentes necessidades estruturais. Essas vigas podem ser projetadas como mistas quando existir uma conexao de cisalhamento com a laje de concreto. Em vigas mistas continuas e semicontinuas, na regiao de momentos negativos,parte do perfil de aco esta comprimida, podendo ocorrer uma instabilidade denominada flambagem lateral com distorcao (FLD), caracterizada por deslocamento lateral e giro da mesa inferior mediante a distorcao da alma do perfil. A ABNT NBR 8800:2008 fornece um procedimento aproximado para verificacao desse estado limite em vigas mistas com perfis de aco de alma cheia, pelo qual se obtem o momento fletor resistente a FLD a partir do momento critico elastico (Mcr) e da rigidez rotacional da viga mista. Para a obtencao dessa rigidez, faz-se necessario determinar o valor da rigidez rotacional de cada elemento (laje, alma do perfil e conexao de cisalhamento) isoladamente. Neste trabalho, uma formulacao analitica foi desenvolvida para a rigidez rotacional da alma de vigas mistas com perfil de aco celular. Adicionalmente, uma analise numerica com modelos em elementos finitos confirmou a aplicabilidade da formulacao, mostrando-a confiavel para o calculo do Mcr a FLD. Keywords: Perfil Celular, Rigidez Rotacional, Flambagem Lateral com Distorcao.
Revista Sul-americana de Engenharia Estrutural, 2018
As novas tendências arquitetônicas e as exigências de mercado levam a engenharia a conceber estru... more As novas tendências arquitetônicas e as exigências de mercado levam a engenharia a conceber estruturas capazes de vencer grandes vãos com um número mínimo de pilares, permitindo assim uma maior flexibilidade arquitetônica. Essa filosofia de projeto tem conduzido a elementos estruturais cada vez mais esbeltos e com frequências naturais cada vez mais baixas, portanto, mais próximas das faixas de frequência das excitações dinâmicas associadas a atividades rítmicas humanas. Face ao exposto, a verificação do estado limite de serviço de vibrações excessivas e o atendimento aos critérios normativos de conforto humano se tornaram relevantes já na fase de concepção arquitetônica, antes mesmo da elaboração do projeto. Dentro desse contexto, este artigo faz um levantamento do desenvolvimento histórico das pesquisas referentes ao comportamento dinâmico de diferentes sistemas de pisos utilizados em estruturas de aço e dos principais critérios normativos relacionados ao tema em questão.
Resumo. Nas regioes de momento negativo de vigas mistas continuas pode ocorrer a flambagem latera... more Resumo. Nas regioes de momento negativo de vigas mistas continuas pode ocorrer a flambagem lateral com distorcao (FLD). A verificacao a FLD pela ABNT NBR 8800:2008 tem como procedimento inicial determinar o momento critico elastico que depende, dentre outros fatores, da distribuicao do momento fletor no vao analisado, considerada por meio do parâmetro de modificacao Cdist. Para avaliar a formulacao analitica prescrita pela norma ABNT NBR 8800:2008, nesse trabalho, modelos numericos em elementos finitos, que representam o comportamento a FLD de vigas mistas foram desenvolvidos. As diferentes condicoes de contorno apresentadas na ABNT NBR 8800:2008 foram modeladas, o que permitiu avaliar o parâmetro de modificacao Cdist. Dessa forma, a influencia da distribuicao do momento fletor foi analisada e importantes conclusoes foram obtidas, como por exemplo, que a formulacao proposta pela ABNT NBR 8800:2008 pode conduzir a resultados contrarios a seguranca para vaos internos de vigas mistas c...
The composite floor system, composed of steel deck and concrete slab, generates more efficient an... more The composite floor system, composed of steel deck and concrete slab, generates more efficient and economical structures. On the other hand, the design of this type of structure has a high complexity level due to the consideration of several variables. In this respect, the objective of this paper is to present the formulation of the optimization problem for a composite floor system (steel and concrete) considering such environmental as economic impacts. To formulate the optimization problem, the reduction of environmental impact was adopted as an objective function - assuming the CO2 emission and the finance cost as parameters. The restrictions were taken by the limiting states imposed in standard NBR 8800:2008. The computer program was developed via Matlab R2016a and the optimization process was carried out using the Genetic Algorithm toolbox existing in this platform. Two application examples of the formulation at hand are presented: the first from the literature and the second fr...
Architectural new tendencies along with current market demands are taking engineering design towa... more Architectural new tendencies along with current market demands are taking engineering design towards the use of flooring systems which can span great distances with a minimum number of columns allowing, thus, more architectural flexibility. This design philosophy has conducted to ever more slender structural elements, with ever lower natural frequencies that are, therefore, closer to the frequency bands of dynamic excitations associated to human activities, such as walking. Within this context, this paper studies the behaviour of the following flooring systems: (a) reinforced concrete slabs supported by steel beams, and (b) steel floor plates supported by steel beams. The evaluation of the natural frequencies of the structure and its responses (floor displacements and accelerations) to the walking activity were analyzed by the simplified analytical method of AISC 360-10 code. The flooring systems were modeled using the finite element software ANSYS 14.0TM and the numerical results f...
Adequate dynamic analysis of support frame structures of mechanical equipment is necessary to ens... more Adequate dynamic analysis of support frame structures of mechanical equipment is necessary to ensure not only the comfort of the users, but ensure good conditions for the operation of equipment supported. Studies of dynamics structural and equipment see the difficulty performing real models. This paper conducts a performance check of the support frame structures, according to changes in their connections, considering the loads caused by rotating machinery and compared with the limits of displacements of the structures established by standards of equipment and structures. The use of a computational numerical model that represents the most real way possible system to be analyzed is required. This article is to conduct a study establishing a practical application of dynamic loads caused by rotating equipment on supports with different connections structures using computational models with STRAP software. Models of structures with connections rigid, pinned and semi-rigid, will be made, ...
Prestressed composite steel-concrete structures are scarcely used due to a lack of clear standard... more Prestressed composite steel-concrete structures are scarcely used due to a lack of clear standardized design guidelines and formulations on the subject. The present research aims to present design methodologies for steel-concrete composite beams with external pretension applied via straight tendons. A computer program to perform structural analysis of such beams was developed based on two different methodologies: the first one is presented in ABNT NBR 8800:2008, in which the guidelines for the design of composite beams with compact webs are adjusted to include the effects of the pretension force. The second methodology is extracted from international literature and presents a structural design process based on stress distribution on the beam. Ninety prestressed and thirty non-prestressed beams were analyzed and designed with the aforementioned computer program to evaluate the influence of beam length, degree of symmetry of the steel profile and eccentricity of the pretension force o...
In the region of negative bending moments of continuous and semi-continuous steel and concrete co... more In the region of negative bending moments of continuous and semi-continuous steel and concrete composite beams, the inferior portion of the steel section is subjected to compression while the top flange is restricted by the slab, which may cause a global instability limit state know as lateral distortional buckling (LDB) characterized by a lateral displacement and rotation of the bottom flange with a distortion of the section’s web when it doesn’t have enough flexural rigidity. The ABNT NBR 8800:2008 provides an approximate procedure for the verification of this limit state, in which the resistant moment to LDB is obtained from the elastic critical moment in the negative moment region. One of the essential parameters for the evaluation of the critical moment is the composite beam’s rotational rigidity. This procedure is restricted only to to steel and concrete composite beams with sections that have plane webs. In this paper, an equation for the calculation of the rotational rigidit...
Revista Sul-americana de Engenharia Estrutural, 2017
Nas vigas mistas de aço e concreto contínuas, nas regiões de momento negativo, deve ser verificad... more Nas vigas mistas de aço e concreto contínuas, nas regiões de momento negativo, deve ser verificado o estado limite último de flambagem lateral com distorção (FLD). A norma brasileira de projeto de estruturas mistas de aço e concreto, ABNT NBR 8800:2008, fornece um procedimento aproximado para verificação desse estado limite com base no comportamento do mecanismo “U” invertido. O momento resistente à FLD é obtido a partir do momento crítico elástico de um modelo analítico constituído pelo perfil de aço e uma mola de rigidez igual à rigidez rotacional da viga mista, que simula o comportamento do mecanismo “U” invertido. Neste trabalho, modelos numéricos foram desenvolvidos, via método dos elementos finitos, para se estudar o comportamento das vigas mistas contínuas de alma plana em regiões de momento negativo, com ênfase na determinação da rigidez rotacional dessas vigas e avaliação do procedimento adotado pela ABNT NBR 8800:2008 para sua obtenção. Foram avaliadas as contribuições das...
In hogging bending moment regions of continuous composite beams the collapse by lateral-distortio... more In hogging bending moment regions of continuous composite beams the collapse by lateral-distortional buckling (LDB) can occur. The design against LDB according to ABNT NBR 8800:2008 begins with the determination of the elastic critical moment, which depends, among other factors, of the distribution of the bending moment in the analyzed span, taken into account in the formulation through the modification parameter Cdist. To assess the analytical formulations prescribed by ABNT NBR 8800:2008, numerical FE models that simulate the LDB behavior of continuous steel-concrete composite beams were developed in this paper. The different boundary conditions presented in ABNT NBR 8800:2008 were checked using two different models: a simplified model, with a single simply supported span; and models with multiple internal supports and more than one span. It was observed that the Cdist values prescribed by ABNT NBR 8800:2008 can be unsafe, and therefore new values for Cdist are proposed in this pa...
With the advancement technology for reinforced concrete structures, it becomes increasingly feasi... more With the advancement technology for reinforced concrete structures, it becomes increasingly feasible to use this technology for steel structures. The objective of this work is to present the formulation of the optimization problem of steel beams with external pretension with straight or polygonal tracing cables, considering the environmental and economic impacts. For the objective function formulation, the minimization of CO2 emission and cost in the design of the structure was considered. As constraints were established the states limits imposed by ABNT NBR 8800:2008. The program was developed within the MATLAB Platform (2016) and the optimization problem solution was obtained through the native Genetic Algorithms method. Routine validation was performed using examples found in the literature and an analysis of the predominant collapse modes was performed. The results indicate that monosymmetric profiles have gains when it comes to reducing CO2 emissions and cost when compared to d...
The literature has well established prestressing in concrete beams and its calculation procedures... more The literature has well established prestressing in concrete beams and its calculation procedures. However, its use in composite steel-concrete beams has increased despite main normative codes lacking a specific approach for it. Designers must, in most cases, combine the available criteria to calculate the standards of steel and reinforced concrete structures. This study aimed to formulate this optimization problem and analyze CO2 emissions for the optimal design of composite steel-concrete beams with external prestressing. The design variables for the optimization problem include cross-section of laminated or welded profiles, slab height, characteristic strength of concrete to compression, and number of tendons. We obtained a solution for the optimization problem via a genetic algorithm (GA) and a particle swarm optimization one (PSO). Comparative analysis with experimental example and with optimization problem of prestressed steel beam are performed. An parametric analysis to seve...
Revista Interdisciplinar de Pesquisa em Engenharia - RIPE, Jan 25, 2017
Abstract. Vigas de aco celulares sao fabricadas de perfis laminados com aberturas circulares padr... more Abstract. Vigas de aco celulares sao fabricadas de perfis laminados com aberturas circulares padronizadas e foram criadas devido a diferentes necessidades estruturais. Essas vigas podem ser projetadas como mistas quando existir uma conexao de cisalhamento com a laje de concreto. Em vigas mistas continuas e semicontinuas, na regiao de momentos negativos,parte do perfil de aco esta comprimida, podendo ocorrer uma instabilidade denominada flambagem lateral com distorcao (FLD), caracterizada por deslocamento lateral e giro da mesa inferior mediante a distorcao da alma do perfil. A ABNT NBR 8800:2008 fornece um procedimento aproximado para verificacao desse estado limite em vigas mistas com perfis de aco de alma cheia, pelo qual se obtem o momento fletor resistente a FLD a partir do momento critico elastico (Mcr) e da rigidez rotacional da viga mista. Para a obtencao dessa rigidez, faz-se necessario determinar o valor da rigidez rotacional de cada elemento (laje, alma do perfil e conexao de cisalhamento) isoladamente. Neste trabalho, uma formulacao analitica foi desenvolvida para a rigidez rotacional da alma de vigas mistas com perfil de aco celular. Adicionalmente, uma analise numerica com modelos em elementos finitos confirmou a aplicabilidade da formulacao, mostrando-a confiavel para o calculo do Mcr a FLD. Keywords: Perfil Celular, Rigidez Rotacional, Flambagem Lateral com Distorcao.
Revista Sul-americana de Engenharia Estrutural, 2018
As novas tendências arquitetônicas e as exigências de mercado levam a engenharia a conceber estru... more As novas tendências arquitetônicas e as exigências de mercado levam a engenharia a conceber estruturas capazes de vencer grandes vãos com um número mínimo de pilares, permitindo assim uma maior flexibilidade arquitetônica. Essa filosofia de projeto tem conduzido a elementos estruturais cada vez mais esbeltos e com frequências naturais cada vez mais baixas, portanto, mais próximas das faixas de frequência das excitações dinâmicas associadas a atividades rítmicas humanas. Face ao exposto, a verificação do estado limite de serviço de vibrações excessivas e o atendimento aos critérios normativos de conforto humano se tornaram relevantes já na fase de concepção arquitetônica, antes mesmo da elaboração do projeto. Dentro desse contexto, este artigo faz um levantamento do desenvolvimento histórico das pesquisas referentes ao comportamento dinâmico de diferentes sistemas de pisos utilizados em estruturas de aço e dos principais critérios normativos relacionados ao tema em questão.
Resumo. Nas regioes de momento negativo de vigas mistas continuas pode ocorrer a flambagem latera... more Resumo. Nas regioes de momento negativo de vigas mistas continuas pode ocorrer a flambagem lateral com distorcao (FLD). A verificacao a FLD pela ABNT NBR 8800:2008 tem como procedimento inicial determinar o momento critico elastico que depende, dentre outros fatores, da distribuicao do momento fletor no vao analisado, considerada por meio do parâmetro de modificacao Cdist. Para avaliar a formulacao analitica prescrita pela norma ABNT NBR 8800:2008, nesse trabalho, modelos numericos em elementos finitos, que representam o comportamento a FLD de vigas mistas foram desenvolvidos. As diferentes condicoes de contorno apresentadas na ABNT NBR 8800:2008 foram modeladas, o que permitiu avaliar o parâmetro de modificacao Cdist. Dessa forma, a influencia da distribuicao do momento fletor foi analisada e importantes conclusoes foram obtidas, como por exemplo, que a formulacao proposta pela ABNT NBR 8800:2008 pode conduzir a resultados contrarios a seguranca para vaos internos de vigas mistas c...
The composite floor system, composed of steel deck and concrete slab, generates more efficient an... more The composite floor system, composed of steel deck and concrete slab, generates more efficient and economical structures. On the other hand, the design of this type of structure has a high complexity level due to the consideration of several variables. In this respect, the objective of this paper is to present the formulation of the optimization problem for a composite floor system (steel and concrete) considering such environmental as economic impacts. To formulate the optimization problem, the reduction of environmental impact was adopted as an objective function - assuming the CO2 emission and the finance cost as parameters. The restrictions were taken by the limiting states imposed in standard NBR 8800:2008. The computer program was developed via Matlab R2016a and the optimization process was carried out using the Genetic Algorithm toolbox existing in this platform. Two application examples of the formulation at hand are presented: the first from the literature and the second fr...
Architectural new tendencies along with current market demands are taking engineering design towa... more Architectural new tendencies along with current market demands are taking engineering design towards the use of flooring systems which can span great distances with a minimum number of columns allowing, thus, more architectural flexibility. This design philosophy has conducted to ever more slender structural elements, with ever lower natural frequencies that are, therefore, closer to the frequency bands of dynamic excitations associated to human activities, such as walking. Within this context, this paper studies the behaviour of the following flooring systems: (a) reinforced concrete slabs supported by steel beams, and (b) steel floor plates supported by steel beams. The evaluation of the natural frequencies of the structure and its responses (floor displacements and accelerations) to the walking activity were analyzed by the simplified analytical method of AISC 360-10 code. The flooring systems were modeled using the finite element software ANSYS 14.0TM and the numerical results f...
Adequate dynamic analysis of support frame structures of mechanical equipment is necessary to ens... more Adequate dynamic analysis of support frame structures of mechanical equipment is necessary to ensure not only the comfort of the users, but ensure good conditions for the operation of equipment supported. Studies of dynamics structural and equipment see the difficulty performing real models. This paper conducts a performance check of the support frame structures, according to changes in their connections, considering the loads caused by rotating machinery and compared with the limits of displacements of the structures established by standards of equipment and structures. The use of a computational numerical model that represents the most real way possible system to be analyzed is required. This article is to conduct a study establishing a practical application of dynamic loads caused by rotating equipment on supports with different connections structures using computational models with STRAP software. Models of structures with connections rigid, pinned and semi-rigid, will be made, ...
Prestressed composite steel-concrete structures are scarcely used due to a lack of clear standard... more Prestressed composite steel-concrete structures are scarcely used due to a lack of clear standardized design guidelines and formulations on the subject. The present research aims to present design methodologies for steel-concrete composite beams with external pretension applied via straight tendons. A computer program to perform structural analysis of such beams was developed based on two different methodologies: the first one is presented in ABNT NBR 8800:2008, in which the guidelines for the design of composite beams with compact webs are adjusted to include the effects of the pretension force. The second methodology is extracted from international literature and presents a structural design process based on stress distribution on the beam. Ninety prestressed and thirty non-prestressed beams were analyzed and designed with the aforementioned computer program to evaluate the influence of beam length, degree of symmetry of the steel profile and eccentricity of the pretension force o...
In the region of negative bending moments of continuous and semi-continuous steel and concrete co... more In the region of negative bending moments of continuous and semi-continuous steel and concrete composite beams, the inferior portion of the steel section is subjected to compression while the top flange is restricted by the slab, which may cause a global instability limit state know as lateral distortional buckling (LDB) characterized by a lateral displacement and rotation of the bottom flange with a distortion of the section’s web when it doesn’t have enough flexural rigidity. The ABNT NBR 8800:2008 provides an approximate procedure for the verification of this limit state, in which the resistant moment to LDB is obtained from the elastic critical moment in the negative moment region. One of the essential parameters for the evaluation of the critical moment is the composite beam’s rotational rigidity. This procedure is restricted only to to steel and concrete composite beams with sections that have plane webs. In this paper, an equation for the calculation of the rotational rigidit...
Revista Sul-americana de Engenharia Estrutural, 2017
Nas vigas mistas de aço e concreto contínuas, nas regiões de momento negativo, deve ser verificad... more Nas vigas mistas de aço e concreto contínuas, nas regiões de momento negativo, deve ser verificado o estado limite último de flambagem lateral com distorção (FLD). A norma brasileira de projeto de estruturas mistas de aço e concreto, ABNT NBR 8800:2008, fornece um procedimento aproximado para verificação desse estado limite com base no comportamento do mecanismo “U” invertido. O momento resistente à FLD é obtido a partir do momento crítico elástico de um modelo analítico constituído pelo perfil de aço e uma mola de rigidez igual à rigidez rotacional da viga mista, que simula o comportamento do mecanismo “U” invertido. Neste trabalho, modelos numéricos foram desenvolvidos, via método dos elementos finitos, para se estudar o comportamento das vigas mistas contínuas de alma plana em regiões de momento negativo, com ênfase na determinação da rigidez rotacional dessas vigas e avaliação do procedimento adotado pela ABNT NBR 8800:2008 para sua obtenção. Foram avaliadas as contribuições das...
In hogging bending moment regions of continuous composite beams the collapse by lateral-distortio... more In hogging bending moment regions of continuous composite beams the collapse by lateral-distortional buckling (LDB) can occur. The design against LDB according to ABNT NBR 8800:2008 begins with the determination of the elastic critical moment, which depends, among other factors, of the distribution of the bending moment in the analyzed span, taken into account in the formulation through the modification parameter Cdist. To assess the analytical formulations prescribed by ABNT NBR 8800:2008, numerical FE models that simulate the LDB behavior of continuous steel-concrete composite beams were developed in this paper. The different boundary conditions presented in ABNT NBR 8800:2008 were checked using two different models: a simplified model, with a single simply supported span; and models with multiple internal supports and more than one span. It was observed that the Cdist values prescribed by ABNT NBR 8800:2008 can be unsafe, and therefore new values for Cdist are proposed in this pa...
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Papers by Adenilcia Fernanda Groberio Calenzani