Reliability-based evaluation of design code provisions for circular concrete-filled steel columns

Beck, André Teófilo; Oliveira, Walter Luiz Andrade de; Nardim, Silvana De; Debs, Ana Lúcia Homce de Cresce El

doi:10.1016/j.engstruct.2009.05.004

Cited by 52 publications

(29 citation statements)

References 12 publications

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“…This is a measure of the ratio between the strength of a structural element, a given by a simplified calculation model, and the actual strength, as tested. For steel-concrete composite columns under centric axial load, some information on model errors exist [7,8,14]. However, our literature survey resulted in no such results for eccentric loading.…”

Section: Model Errormentioning

confidence: 50%

“…The calibration process for NBR 8800 was studied in [6], but the suggested safety factors were never incorporated in the actual code. In the specific case of composite structures, only isolated evaluations of safety factors are found in the literature [7][8][9][10][11]. The main objective of this work is to study the safety of partially-encased steel-concrete composite columns (Figure 1), submitted to compressive bending, and designed according to NBR 8800 [1].…”

Section: Introductionmentioning

confidence: 99%

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Reliability of partially encased steel-concrete composite columns under eccentric loading

Pereira

Beck

Debs

2017

Rev. IBRACON Estrut. Mater.

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ResumoThe Brazilian design code for composite buildings (NBR8800) has never been subject to a reliability-based calibration of the partial factors used in design. As a consequence, the level of structural safety achieved by using these factors is, in general, unknown. This paper presents a study of the reliability of partially encased steel-concrete composite columns, subject to compression and bending. Literature statistics are used to quantify uncertainty in strength of structural materials and in loads. Reliability indexes are evaluated, via FORM, for two ratios between dead and live loads, and for some values of load eccentricity. It was found that larger load eccentricity leads to a reduction in reliability indexes. These values are larger than minimum values recommended in international design codes; hence one concludes that design of such columns using NBR8800 leads to acceptable safety levels.Keywords: reliability, composite column, structural safety.A norma brasileira que embasa o projeto estrutural de edifícios contendo elementos mistos (NBR8800) nunca passou pelo processo de calibração, baseada em confiabilidade, dos coeficientes parciais de segurança utilizados em projeto. Como consequência, o nível de segurança obtido com o uso destes coeficientes é, em geral, desconhecido. Este trabalho apresenta um estudo da confiabilidade estrutural de pilares mistos de aço-concreto, parcialmente revestidos e submetidos à flexo-compressão. Estatísticas da literatura são utilizadas para caracterizar as incertezas nas propriedades dos materiais constituintes e nas ações. Índices de confiabilidade (β) são avaliados, via FORM, para duas razões entre ação permanente e ação variável, e para alguns valores de excentricidade da ação vertical. Verifica-se que o índice de confiabilidade dos pilares mistos diminui com o aumento da excentricidade de projeto. Estes valores estão acima de índices de confiabilidade mínimos sugeridos em normas internacionais, o que sugere que o projeto utilizando a norma NBR8800 resulta em colunas mistas seguras.Palavras-chave: confiabilidade; pilares mistos; segurança estrutural.

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Section: Model Errormentioning

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Reliability of partially encased steel-concrete composite columns under eccentric loading

Pereira

Beck

Debs

2017

Rev. IBRACON Estrut. Mater.

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“…The calibration was conducted ensuring that the safety level of the new codes reflected the general safety level of old codes, which was regarded as result of collective knowledge and experience-based optimization over the years. This process was well documented in the literature (Ellingwood et al, 1980;Ellingwood and Galambos, 1982).…”

Section: Introductionmentioning

confidence: 66%

“…Recent studies by the authors (Beck and Dória, 2008;Oliveira et al, 2008;Beck et al, 2009) reveal that the reliability index of structures designed according to Brazilian code NBR8800:2008 lie in the range from β = 2.3 to β = 4.5. Therefore, in this study, the target reliability index was first selected as β T = 3.0.…”

Section: Partial Factors To Obtain β β β β T = 30 Exactlymentioning

confidence: 99%

A first attempt towards reliability-based calibration of Brazilian structural design codes

Beck¹,

Souza²

2010

J. Braz. Soc. Mech. Sci. & Eng.

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“…This work is part of a larger project about the calibration, based on structural reliability, of the partial factors from Brazilian design codes. The calibration is being developed by the authors of this paper, though it has already been addressed in a preliminary way by Beck and Doria [5], Beck et al [6], Chaves et al [7] and Beck and Souza Jr. [8].…”

Section: Introductionmentioning

confidence: 99%

A new study of Brazilian concrete strength conformance

Santiago

Beck²

2017

Rev. IBRACON Estrut. Mater.

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A new study of Brazilian concrete strength conformance Um novo estudo da conformidade da resistência do concreto produzido no Brasil Abstract ResumoThis paper presents a new evaluation of the strength compliance of concretes produced in Brazil. It is based on experimental results of over twenty-seven thousand concrete samples from different parts of the country. Results show that a significant part of Brazilian concrete do not reach the characteristic strength (fck) specified in design, and the percentage of nonconforming samples tend to be higher than 5%. This study also reveals the concrete produced in the South and Midwest regions have less variability than the ones produced in the other regions of the country. These results emphasize the importance of a rigorous control in manufacturing and reception of concretes in order to reduce the nonconforming cases.Keywords: concrete strength compliance, concrete structures, structural safety.Este artigo apresenta uma nova avaliação da conformidade dos concretos atualmente produzidos no Brasil. Ela está pautada em resultados de ensaios de resistência à compressão axial de mais de vinte e sete mil corpos de prova de concretos moldados in loco, no ato de seu recebimento, em diferentes obras do país. Os resultados mostram que parte do concreto produzido no Brasil não alcança a resistência característica (fck) prevista em projeto, e que o percentual de amostras não conformes tende a ser superior a 5%. Este estudo também evidencia que os concretos produzidos nas regiões Sul e Centro-Oeste apresentam menor variabilidade que aqueles produzidos nas demais regiões do país. Estes resultados reforçam a importância de um controle rigoroso na fabricação e no recebimento do concreto visando diminuir a ocorrência de não conformidades.Palavras-chave: conformidade da resistência do concreto, estruturas de concreto, segurança das estruturas.

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Reliability-based evaluation of design code provisions for circular concrete-filled steel columns

Cited by 52 publications

References 12 publications

Reliability of partially encased steel-concrete composite columns under eccentric loading

Reliability of partially encased steel-concrete composite columns under eccentric loading

A first attempt towards reliability-based calibration of Brazilian structural design codes

A new study of Brazilian concrete strength conformance

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