Influence of pipe steel heterogeneity of the upper bound tensile strain capacity of pipeline girth welds: A validation study

• Pipe steel heterogeneity can reduce the tensile strain capacity of girth welds.
• A theoretical framework aims to predict this reduction.
• The framework is experimentally validated using CWP test results.
• A stepwise approach for practical application is provided.

The strain capacity of flawed girth welds is influenced by the constitutive properties of the connected pipes. Although most defect assessment procedures assume equal properties for both pipes, line pipe steel standards recognize significant variability. A recent theoretical framework provides an upper bound equation of tensile strain capacity based on pipe steel heterogeneity (and regardless of weld properties). This paper validates the equation using 64 curved wide plate test results. A strain capacity prediction method adjusted for heterogeneity is developed, allowing to adopt existing strain capacity equations for welds connecting homogeneous pipes. Its applicability to pressurized pipelines is discussed.