Corrosion and Safety of Structures in Marine Environments

This chapter provides an overview of the approaches that can be used to determine structural reliability based analytic safety assessment for steel structures corroding in marine environments. Corrosion and pitting of structural steels used in marine pipelines and for off-shore mooring chain are important factors in continued integrity and service performance and are best considered in a reliability framework. For steel structures fatigue, corrosion and various combinations are likely to be very aggressive. The actual corrosion losses and maximum pit depths develop in a strongly non-linear fashion with increasing exposure period. In corrosion engineering it is usual to think in terms of a 'corrosion rate'. This assumes that corrosion continues at a constant rate with time. Steel composition has been found to have little effect on the development of pitting corrosion in marine immersion conditions. Importantly, marine corrosion can be influenced by the involvement of microorganisms particularly in nutrient polluted waters.