Reliability algorithms applied to reinforced concrete structures durability assessment

Nogueira, Caio Gorla; Leonel, Edson Denner; Coda, Humberto Breves

doi:10.1590/s1983-41952012000400003

Cited by 15 publications

(16 citation statements)

References 21 publications

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“…Considering that this failure mode does not compromise the structural integrity of the deck, the limit state assumed here shall be considered as a serviceability limit state. Consequently, a target reliability index βlim=1.30 is assumed here (Nogueira, Leonel, & Coda, 2012). Given the medium-high relative economic costs associated to bridge deck cover replacement, and given the small consequences of the proposed failure, such target reliability index is in good accordance with the recommendations of standards and codes such as ISO (2015) and JCSS (2001).…”

Section: Reliability-based Maintenancementioning

confidence: 99%

Sustainability assessment of concrete bridge deck designs in coastal environments using neutrosophic criteria weights

Navarro

2019

Structure and Infrastructure Engineering

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Essential infrastructures such as bridges are designed to provide a long-lasting and intergenerational functionality. In those cases, sustainability becomes of paramount importance when the infrastructure is exposed to aggressive environments which can jeopardize their durability and lead to significant maintenance demands. The assessment of sustainability is however often complex and uncertain. The present study assesses the sustainability performance of 16 alternative designs of a concrete bridge deck in a coastal environment on the basis of a neutrosophic group Analytic Hierarchy Process (AHP). The use of neutrosophic logic in the field of multi-criteria decision-making, as a generalisation of the widely used fuzzy logic, allows for a proper capture of the vagueness and uncertainties of the judgements emitted by the decision makers. TOPSIS technique is then used to aggregate the different sustainability criteria. From the results, it is derived that only the simultaneous consideration of the economic, environmental and social life cycle impacts of a design shall lead to adequate sustainable designs. Choices made on the basis of the optimality of a design in only some of the sustainability pillars will lead to erroneous conclusions. The use of concrete with silica fume has resulted in a sustainability performance 46.3% better than conventional concrete designs.

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Section: Reliability-based Maintenancementioning

confidence: 99%

Sustainability assessment of concrete bridge deck designs in coastal environments using neutrosophic criteria weights

Navarro

2019

Structure and Infrastructure Engineering

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“…On the basis of these values, the failure probability at any time t shall be evaluated by means of Monte Carlo simulations, considering that failure occurs when the chloride concentration exceeds the critical chloride content at the rebar depth, namely 40 mm (standard deviation is 2 mm). Maintenance is mandatory at the time when the reliability β(t) reaches β lim = 1.3 [21]. Maintenance is optimized by finding the particular time t ≤ t lim for which the resulting life cycle negative impacts are minimized.…”

Section: Reliability-based Maintenance Demandmentioning

confidence: 99%

Role of the Social Dimension in the Sustainability-Oriented Maintenance Optimization of Bridges in Coastal Environments

Navarro

Yepes

Martí

2020

WIT Transactions on the Built Environment

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The recently established Sustainable Development Goals recognize the importance of infrastructures for achieving a sustainable future. Along their long-lasting life cycle, infrastructures generate a series of impacts, the reduction of which has been one of the main focus of researchers' attention in past years. The optimization of maintenance intervals of structures, such as bridges, has aroused the attention of the civil engineering sector, since most of the impacts of infrastructures occur during the operational phase. Thus, bridges are currently designed to attend the economic and environmental impacts derived from maintenance activities. However, the social pillar of sustainability is usually neglected in those analyses. Since no universally accepted methodology does yet exist for its consistent evaluation, the social dimension is not effectively included in the life cycle assessments of infrastructures. This communication evaluates the life cycle impacts of alternative concrete bridge deck designs in a maintenance-demanding environment near shore. Reliability-derived maintenance intervals are first optimized by minimizing the economic and environmental impacts. In a second stage of the analysis, the social dimension is included in the optimization process and results are compared. Optimization results from these combined assessments are obtained applying the multi-criteria decision-making technique AHP-TOPSIS. The present paper demonstrates how the inclusion of the social dimension may lead to different, more sustainably-oriented optimal maintenance strategies. The three-dimensional approach applied here has resulted in other alternatives being preferred to those derived from the conventional assessment that considers the economic and environmental perspectives. Such findings support the idea that holistic life cycle assessments are required for sustainable designs of infrastructures and that more efforts are urgently needed to integrate the social dimension in sustainability assessments of structures.

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“…Many engineering problems of chloride ingress, as those discussed in this study, can be solved considering this simplification. For a semi-infinite domain with an uniform fluid concentration at the external surface, the second Fick's law can be written as follows [13][14][15]17]:…”

Section: Fick's Lawmentioning

confidence: 99%

“…The function ( ) i x I can be estimated as follows: (13) By simulating the limit state function for a convenient range of sampling, the mean value of ( ) i x I will be an estimator for the probability of failure. Therefore:…”

Section: )mentioning

confidence: 99%

“…In this model, the Fick's law was applied to represent the chloride diffusion process along time, empirical laws were adopted for the quantification of reinforcement's cross section loss and the Monte Carlo simulation method was used to carried out the probabilistic analysis. Nogueira et al [13] performed a study on the determination of corrosion start using a probabilistic approach by the coupling between Fick's law and reliability theory. In this work, the influence of uncertainties associated with concrete cover depth and water-cement ratio on the probability of structural life failure was analysed.…”

Section: Introductionmentioning

confidence: 99%

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Influence of reinforcement's corrosion into hyperstatic reinforced concrete beams: a probabilistic failure scenarios analysis

Pellizzer

Leonel

Nogueira

2015

Rev. IBRACON Estrut. Mater.

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ResumoThis work aims to study the mechanical effects of reinforcement's corrosion in hyperstatic reinforced concrete beams. The focus is the probabilistic determination of individual failure scenarios change as well as global failure change along time. The limit state functions assumed describe analytically bending and shear resistance of reinforced concrete rectangular cross sections as a function of steel and concrete resistance and section dimensions. It was incorporated empirical laws that penalize the steel yield stress and the reinforcement's area along time in addition to Fick's law, which models the chloride penetration into concrete pores. The reliability theory was applied based on Monte Carlo simulation method, which assesses each individual probability of failure. The probability of global structural failure was determined based in the concept of failure tree. The results of a hyperstatic reinforced concrete beam showed that reinforcements corrosion make change into the failure scenarios modes. Therefore, unimportant failure modes in design phase become important after corrosion start.Keywords: reinforcements corrosion, chlorides ingress, Fick's law, reliability, reinforced concrete, failure scenarios.Este trabalho tem como principal objetivo analisar os efeitos da corrosão de armaduras em vigas em concreto armado na alteração dos possíveis cenários de falha individuais e na falha global da estrutura ao longo do tempo. As equações de estado limite consideradas descrevem analiticamente a resistência à flexão e ao esforço cortante em seções transversais retangulares em concreto armado. Foi também incorporada uma lei que penaliza a resistência ao escoamento do aço em função da evolução da corrosão em conjunto com a lei de Fick, a qual modela a penetração de íons cloreto no interior dos poros do concreto. Equações empíricas baseadas na lei de Faraday foram utilizadas para a determinação da nova área de armadura a cada instante de tempo na análise. A teoria da confiabilidade foi aplicada adotando-se o método de simulação de Monte Carlo para a avaliação das probabilidades individuais dos modos de falha considerados. A determinação da probabilidade de falha global da estrutura seguiu um procedimento baseado no conceito de árvore de falhas. Os resultados da análise de uma viga hiperestática em concreto armado demonstram que a corrosão das armaduras pode alterar os cenários de falha, de forma que, modos de falha não importantes na fase de projeto se tornam importantes à medida que o processo corrosivo evolui.Palavras-chave: corrosão de armaduras, ingresso de cloretos, leis de Fick, confiabilidade, concreto armado, cenários de falha.

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Reliability algorithms applied to reinforced concrete structures durability assessment

Cited by 15 publications

References 21 publications

Sustainability assessment of concrete bridge deck designs in coastal environments using neutrosophic criteria weights

Sustainability assessment of concrete bridge deck designs in coastal environments using neutrosophic criteria weights

Role of the Social Dimension in the Sustainability-Oriented Maintenance Optimization of Bridges in Coastal Environments

Influence of reinforcement's corrosion into hyperstatic reinforced concrete beams: a probabilistic failure scenarios analysis

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