Sobre a modelagem numérica da difusão de cloretos no concreto: uma abordagem pelo método dos elementos de contorno com aplicação de modelos de confiabilidade e otimização

Pellizzer, Giovanni Pais

doi:10.11606/t.18.2019.tde-24062019-094143

Cited by 5 publications

(7 citation statements)

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“…Water/cement ratio, type of cement and its hydration process, curing and presence of additions are the main factors related to concrete properties. Finally, mechanical loads can also open up cracks due to tensile stresses, influencing the properties of mass transport (PELLIZZER, 2019).…”

Section: Initiation Periodmentioning

confidence: 99%

“…Among the various phenomena of mass transport, ionic diffusion stands out as the main transport mechanism of chloride ions and, therefore, the initiation stage can be consistently modeled considering it as an isolated mechanism (VU; STEWART, 2000;CHERNIN;STEWART, 2009). Diffusion develops in the presence of a concentration gradient; thus, modeling of diffusion can be adequately approached by Fick's laws (STEWART, 2004;MEDEIROS, 2008;GUZMÁN;GÁLVEZ;SANCHO, 2011;PELLIZZER;LEONEL;NOGUEIRA, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of reinforced concrete beam subject to pitting corrosion

Ramos

Carrazedo

2022

Ambient. constr.

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This paper presents a numerical study about the effects of chloride-induced corrosion on the service life of structures. A two-dimensional geometrically nonlinear mechanical model based on Finite Element Method (FEM) was developed for reinforced concrete structures. The corrosion initiation stage was evaluated by Fick's diffusion laws. The corrosion propagation was carried out by deterministic models based on Faraday's law. Pitting corrosion was simulated in the reinforcements by pit elements, distributed longitudinally on the steel rebars, which degrade the physical properties over time. The service life was determined by the crack width.Two parametric analyses were performed. In the first analysis, five models were created with a variablecover thickness and water/cement ratio (w/c). In the second analysis, the reduction in yield stress due to corrosion was considered.The results showed that the concrete cover thicknessand the w/c ratio significantly influence the service life. The reduction of the cover thickness from 30 mm to 25 mm resulted in 21.26% reduction in service life, whilethe increase in the w/c ratio from 0.50 to 0.55 caused 32.98% reduction in service life of the structural element analyzed.

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Section: Initiation Periodmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of reinforced concrete beam subject to pitting corrosion

Ramos

Carrazedo

2022

Ambient. constr.

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“…The punching shear failure is an occurrence of ULS, with moderate to high failure consequences [47], according to total and building construction costs ratio. Table 2 shows minimum values for β and P f in ULS recommended by the European code EN 1990:2002 [48], for three risk classes, defined by the consequences of failure with 50 years return period [49].…”

Section: Structural Reliability Applied To Punching Shear Analysismentioning

confidence: 99%

Probabilistic analysis of slab-column connections subjected to punching shear according to the ABNT NBR 6118 (2014) recommendations considering the model error measure

Marque

Nogueira

2021

Rev. IBRACON Estrut. Mater.

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Reinforced concrete flat slabs are structural systems in which slabs are directly supported by columns, without the use of beams. A structural phenomenon that deserves attention in these systems is the punching shear, characterized by the occurrence of shear stresses close to the slab-column interface, which can produce fragile rupture in those regions. This study presents some results of reliability index β obtained for slab-column connections based on FORM, according to the Brazilian standard’s model, considering the model error. The critical contours C and C’ without shear reinforcement are analyzed. The results showed that failure in the C contour is very unlikely, while the probabilities of rupture in the C' contour when considering the influence of the model error are greater than the target values recommended in the literature for the ULS.

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“…A técnica de simulação Monte Carlo constitui-se como um método poderoso para essa análise, já que considera simultaneamente os diferentes parâmetros aleatórios envolvidos no problema [27,28]. Assim, a associação de formulações matemáticas representativas das leis de difusão a algoritmos de confiabilidade apresenta uma metodologia eficiente para a modelagem e estimativa da vida útil de estruturas de concreto sujeitas à corrosão, com resultados mais consistentes, abrangentes e confiáveis que as estimativas determinísticas [1,[22][23][24][25][26][27][28][29].…”

Section: Introductionunclassified

Análise probabilística da vida útil de lajes de concreto armado sujeitas à corrosão por carbonatação via simulação de Monte Carlo

Félix

Carrazedo

2021

Matéria (Rio J.)

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RESUMEN O presente trabalho apresenta uma análise mecânico-probabilística de lajes de concreto armado sujeitas à corrosão uniforme, devido à ação do CO2 no concreto, por meio de uma metodologia alternativa que considera formulações analíticas referentes ao comportamento mecânico do concreto acopladas a modelos obtidos via Inteligência Artificial e à técnica de simulação de Monte Carlo. Os períodos de iniciação e propagação da corrosão são determinados por meio do cálculo de probabilidades de ocorrência dos estados limites de despassivação e ruptura à flexão, respectivamente. Os resultados encontrados apontam que, a depender do controle tecnológico do concreto, do cobrimento e do ambiente de exposição, a vida útil pode ser drasticamente reduzida, apresentando em muitos casos confiabilidade estrutural e durabilidade inferior às requisitadas em projeto. A fim de garantir menor probabilidade de falha devido à corrosão por carbonatação, recomenda-se empregar cimentos Portland do tipo CP V, CP II F, CP II E e CP II Z, para a produção de estruturas inseridas em ambientes com alta concentração de CO2. Além disso, os resultados mostram que abordagens puramente determinísticas não são capazes de avaliar adequadamente a vida útil de estruturas de concreto sujeitas ao processo de corrosão, sendo necessário analisar o problema considerando a aleatoriedade dos diferentes parâmetros associados ao processo de deterioração, a fim de representar com fidelidade o processo de corrosão e seus efeitos deletérios.

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Sobre a modelagem numérica da difusão de cloretos no concreto: uma abordagem pelo método dos elementos de contorno com aplicação de modelos de confiabilidade e otimização

Cited by 5 publications

References 0 publications

Numerical analysis of reinforced concrete beam subject to pitting corrosion

Numerical analysis of reinforced concrete beam subject to pitting corrosion

Probabilistic analysis of slab-column connections subjected to punching shear according to the ABNT NBR 6118 (2014) recommendations considering the model error measure

Análise probabilística da vida útil de lajes de concreto armado sujeitas à corrosão por carbonatação via simulação de Monte Carlo

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