Strain capacity of girth weld joint cracked at “near-seam zone”

Cracking occurs often at “near-seam zone” in the girth weld joint of an X70 pipeline in tensile test, which is considered unacceptable for strain-based design pipelines according to some current standards. The tensile strain capacity of girth weld joints for X70 pipelines with “near-seam zone” cracks has thus been studied via the approach of crack driving force and fracture resistance curve. The high strain capacity has been demonstrated by resistance curve tangency approach and curved wide plate test. The results prove that the girth weld joint has considerable fracture resistance and is thus of high strain capacity.