Direct Tension Performance of Steel Pipelines with Welded Slip Joints

Full-scale direct tension test results are presented in this paper for two steel pipelines with welded slip joints, using high quality external welds, and an outer diameter and wall thickness of 320 and 6.4 mm, (12.5 and 0.25 in.) respectively. The test pipes were loaded to complete circumferential tensile failure. The results of numerical simulations with a two-dimensional axisymmetric solid finite-element (FE) models using the program ABAQUS compare favorably with the experimental measurements. The FE results show that pipelines in the field with high quality welds can sustain maximum tensile strain of about 0.03 even with internal pressure. Assuming good welds, an allowable tensile strain level of 0.01 to 0.015 is recommended. The test results are discussed with respect to welding and inspection practices, as well as their application in the design and risk assessment of pipelines subject to large ground deformation caused by earthquakes, landslides, and subsidence.