Developments in Methods for Assessing the Remaining Strength of Corroded Pipelines

Extensive research has been carried out for many years by PRCI to develop methods for assessing the remaining strength of corroded pipelines. This has led to the development of assessment methods such as ASME B31G and RSTRENG. Research by others such as Advantica has developed new criteria such as the LPC method and extended the range of assessment methods to include numerical analysis. While there has been substantial progress, there remain areas where existing criteria require improvements. The improvements identified include limitations on the interaction of closely spaced defects; the effects of external loading, and cyclic pressure loading. Furthermore, as operators start to use higher strength materials there will be an increasing need to assess the integrity of corroded high strength pipelines and to further validate the application of existing criteria and models for these materials. PRCI and the US DOT have funded research to address these issues in recent years. The work has comprised a programme of materials testing, finite element analyses and full scale burst testing to develop methods for assessing corrosion damage in pipelines of strength grade up to X100. This paper gives an overview of the development work.