DOI
10.11606/D.18.2017.tde-27042017-092200
Documento
Autor
Nome completo
Karolinne Oliveira Coelho
Área do Conhecimento
Data de Defesa
Imprenta
São Carlos, 2017
Leonel, Edson Denner (Presidente)
Flórez-Lopez, Julio
Vieira Junior, Luiz Carlos Marcos
Título em português
Palavras-chave em português
Carbonatação
Cloretos
Mecânica do dano
Resumo em português
Título em inglês
Numerical models applied to the probabilistic modelling of the mechanical degradation of concrete and reinforcement corrosion
Palavras-chave em inglês
Carbonation
Chlorides
Damage mechanics
Lumped damage theory
Reinforced concrete
Reinforcement corrosion
Structural reliability
Resumo em inglês
The reinforcement's corrosion is one of the most common causes of mechanical degradation in reinforced concrete structures. This process leads to the reduction of the service life and, consequently, economic loss. Thereby, this study aims to contribute with the analysis of the phenomena associated to the mechanical degradation of reinforced concrete, due to the carbonation and the chloride ions. For this purpose, analytical models based on second Fick's law are used to quantify CO2 and chloride ions diffusion, which enables to determine the corrosion time initiation. The mechanical degradation of reinforced concrete structures is modeles by the lumped damage model which accounts for stiffness loss, reinforcement mass loss and yield stress reduction due to the corrosive process. The lumped damage formulation was modified to include the state corrosion variable and the corrosion evolution law based on semi-empirical equations available in the literature. These equations determine the reinforcement's diameter reduction and the loss of resistant capacity of the reinforcement's bar. The corrosion problem is formulated as a stochastic process and solved by the Monte Carlo simulation for two examples: an isostatic beam and a hyperstatic frame. The limit state functions are based on the acceptable damage value. Curves of probability of corrosion initiation and probability of failure are obtained over a range of 50 years. In the hyperstatic case, the most probable failure path, also named the critical path, is determined. It is observed that the corrosive process causes changes on the critical path and, therefore, it must be accounted on structural repair analysis. Damage and probability of failure maps were developed to show the changes on the structural behavior due to the corrosion.

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Data de Publicação
2017-05-10

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