Atteris performed assessments on anomalous spans resulting from a 2014 ROV survey of the 2TL pipeline. This included a number of Level 2 and Level 3 assessments to accurately determine the requirement for any intervention work, including interacting spans. The work concluded that all of the reported spans were acceptable without any requirement for intervention.
Further detailed analysis was performed in three key locations where ongoing scour is resulting in significant spanning to redefine the allowable span lengths considering:
The work utilised Atteris in-house version of Fatfree to perform multiple fatigue simulations, as well as Corus 3D, Atteris dynamic stability software, to assess the pipeline stresses due to hydrodynamic loading, resulting in justification to significantly increase the allowable span lengths in 2 of the 3 discrete sections assessed.
