Crack Analysis Due to Fatigue Load During Subsea Pipeline Installation

Most of the subsea pipelines in Indonesia are installed using S-Lay method with pipelay barges equipped mooring spreads, tensioners, and stinger. During pipeline installation, static loads occur due to configuration from firing line barge up seabed. The pipe will experience axial tension bending moment two critical areas: overbend sagbend. In addition, fatigue during installation environmental (i.e., currents waves). Defects that found after welding grow these loads. Crack analysis a fracture mechanic approach known as Engineering Critical Assessment (ECA) is carried out by considering load significant wave height variations for 0.5m, 1.0m, 1.8m. BS 7910 used standard reference determine allowable defects criteria external internal flaws. depth defect (a) simulated 1mm – 3mm. length decreased 12.7% - 25.0% 0.5m 1.8m surface flaw. While an flaw, 5.9% 13.6% These results can be basis contractors perform sensitivity optimize based on actual at site.