Probabilistic analysis of resistance degradation of reinforced concrete bridge beams under corrosion

Bridges subjected to environmental attack can experience changes in resistance which are time-variant. In this study, flexural strength loss in concrete bridge beams due to corrosion of steel reinforcement is considered. The sensitivity of the corrosion initiation time of steel reinforcement to changes in the main descriptors of diffusion related random variables is illustrated. Both the mean and standard deviation of the corrosion initiation time increase with an increase in the coefficient of variation of each of the diffusion related random variables for the range of values considered in this study. An example problem is given which illustrates the effect of various variables including corrosion rate and corrosion initiation time on the time-variant area of steel reinforcement and flexural strength of an existing reinforced concrete bridge beam. For the range of parameters and the damage scenarios considered, the mean value of the resistance loss function appears to increase about linearly with time. The results can be used to develop optimal lifetime reliability-based maintenance strategies for reinforced concrete bridges under environmental attack.

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