Stress Analysis of Underwater Pipeline for Irregular Seabed Topography Using CAESAR II

Offshore oil and gas pipelines are being subjected to deeper water depths, more extreme
environmental conditions, and harsher operating requirements than ever before. Given
these conditions, free spanning pipelines are becoming more common and are often
unavoidable during pipeline installation. Free spans occur as a result of irregular seafloor
topography at installation or during pipeline operation as a result of vibration and scour
[1].
A linear-elastic finite element model is applied to the solution of stress analysis problems
involving submarine pipelines freely resting upon irregular seabed profiles. This report
describes a finite element (FE) modelling procedure and parametric study leading to the
investigation of stress distribution and deformation subjected on pipeline. The objective
of this project is to model underwater pipeline using pipe stress analysis software,
CAESAR II. The pipeline will be examined on various conditions according to the
geometry of the seabed. The input or load cases of the pipeline system are ocean current
and wave. The FE analyses are carried out for both the fully fixed and simply supported
pipes, which form the two extreme conditions of pipelines under service conditions.
Expected result is that the stress of the pipelines should not exceed the maximum
allowable stress set by the regulations.