Reliability of maintained, corrosion protected plates subjected to non-linear corrosion and compressive loads

Abstract

A model is proposed for the non-linear general corrosion wastage in a plate, which is able to describe an initial period without corrosion due to the presence of a corrosion protection system, and an exponential increase in wastage up to a steady-state value. The influence of adopting this model instead of a linear one is demonstrated by studying the reliability of a corrosion-protected plate subjected to compressive loads, and maintenance actions. The paper examines how the plate collapse strength will vary in time as a result of generalised corrosion and plate repair. In the presence of general corrosion, the plate thickness will decrease at a random rate as a function of time and will affect the net plate section resisting the applied load. The collapse strength against compressive loading is described by a function of time and the resulting reliability is quantified. The sensitivity of the reliability estimates with respect to several parameters is also studied. The reliability is predicted by a time-variant formulation and the effects of repair actions in the reliability assessment are shown.