Cyclic Deformation Behavior and Buckling of Pipeline With Local Metal Loss in Response to Axial Seismic Loading

Buried pipelines may be corroded, despite the use of corrosion control measures such as protective coatings and cathodic protection, and buried pipelines may be deformed due to earthquakes. Therefore, it is necessary to ensure the integrity of such corroded pipelines against earthquakes. This study has developed a method to evaluate earthquake resistance of corroded pipelines subjected to seismic motions. Pipes were subjected to artificial local metal loss and axial cyclic loading tests to clarify their cyclic deformation behavior until buckling occurred under seismic motion. As the cyclic loading progressed, displacement shifted to the compression side due to the formation of a bulge. The pipe buckled after several cycles. To evaluate the earthquake resistance of different pipelines with varying degrees of local metal loss, a finite-element analysis method was developed that simulates cyclic deformation behavior. A combination of kinematic and isotropic hardening was used to model the material properties. The associated material parameters were obtained by small specimen tests that consisted of a monotonic tensile test and a low-cycle fatigue test under a specific strain amplitude. This method enabled the successful prediction of cyclic deformation behavior, including the number of cycles required for the buckling of pipes with varying degrees of metal loss.