Fatigue and burst tests of full-scale girth welded pipeline sections for safe operations

Abstract

The main objective of our ongoing research is data collection for integrity management (IM) tasks, in other words for pipeline integrity management system (PIMS), helping the transporting pipeline operators in different decision situations. Either the reserves of the girth welds after a long-term operation can be identified or the girth welds with different defects should be repaired and/or replaced. From the operators’ point of view, the long-term operation is the cost-effective way; however, from the safety point of view, the managing of the lifecycle of the pipeline is the more reliable way. Unfortunately, inadequate girth welds cause catastrophic damages in transporting pipelines, all over the world. Consequently, the optimal operation of the pipelines is a complex task. The paper introduces our investigation program executed on full-scale pipeline sections. Fatigue (100,000 cycles) and burst tests were executed on different pipeline sections containing girth welds. Long-term operated and replaced gas transporting pipeline sections, furthermore, both appropriate and inadequate girth welds were investigated. The testing results and the damage histories were compared with each other; safety factor (SF) was defined and calculated for the assessment of the reliability of the girth welds.