Probabilistic model for marine corrosion of steel for structural reliability assessment

The assessment of the remaining safe and serviceable life of deteriorating structures using structural reliability theory requires realistic models for corrosion. Using existing data it is shown that corrosion is a nonlinear function of time. A probabilistic model for "at-sea" immersion corrosion of mild and low alloy steels based on fundamental physiochemical corrosion mechanics is presented. The mean-value part of the model is made operational by calibrating its parameters to existing and new field data. A simple model for corrosion uncertainty is presented and its initial calibration discussed. More refined calibration awaits field data over practically significant seawater temperature ranges but particularly for lower temperature regimes. Extensions to the model and its application to other exposure regimes are outlined briefly.