The general aim of a recently finalized European project, i.e. EU RFCS SBD-Spipe, is to generate specific know-how concerning the development and possible use of spirally welded pipes for demanding applications. The demanding applications relate especially to structural integrity issues, both onshore and offshore, requiring good performance under application of large strains resulting in buckling, collapse and/or tensile loading. The outcome of this project can also be used as technical basis for improving standards and guidelines, that address design and safety of spirally welded pipelines.
The contribution of Ghent University to this project focusses on the aspects of tearing resistance, defect tolerance and strain capacity of girth welded joints subjected to remote axial tensile load. A numerical and experimental approach is used for the assessment of flaw tolerability and strain development upon tensile loading. Spiral pipes of steel grade API-5L X70 with 36” and 48” diameters have been girth welded using both a manual and semi-automatic welding processes. Curved wide plate specimens have been extracted from the pipes and artificial weld defects have been introduced. The specimens have been loaded in tension up to failure at a temperature of −10°C. This paper reports on the experimental result of a series of curved wide plate tests.