A Numerical Lab to Predict the Strength Capacity of Offshore Pipelines

In the recent years, the offshore pipeline industry has been under pressure to provide solutions for demanding material and line pipe technology problems, installation technology to safely tackle the ultra-deep waters challenge, quantitative prediction of reliable operating lifetime for pipelines under high pressure/high temperature conditions and remedial measures to tackle considerable geo-morphic and human activity related hazards. Future pipelines are being planned in very difficult environments, i.e. crossing ultra-deep water and difficult geo-seismic-morphic conditions. In these circumstances, it is of crucial importance (1) to adopt advanced design procedure and criteria, possibly based on limit state principles recently implemented in the design codes, and (2) to use advanced engineering tools for predicting the strength capacity and the pipeline behaviour during the installation and operational phase, in order to design the pipeline safely and to assess properly the technic-economical feasibility of the project. This paper discusses the relevant failure modes for offshore pipelines, the FE analysis results relevant to the sectional capacity of thick-walled pipes, and the FE analysis results relevant to the global and local response effect of a pipeline, laid on the sea bottom, and subject to a point-load force.