This paper is concerned with a response based method for determining metocean design criteria for offshore pipelines. The method determines a set of metocean parameters that are consistent with the extreme response of the pipeline, and hence, incorporates the dependence between them implicitly. However, there are a number of challenges in its application. Firstly, the loading on a pipeline is dependent on the previous wave cycle, and hence, the drag and inertia coefficients vary within a sea-state. Secondly, along many pipeline routes the waves are depth limited and the short-term distribution of wave induced velocity and pipeline response can be difficult to define. These challenges are overcome through a number of approaches that include a parametric representation of the distribution of the response and the application of multivariate extreme value analysis. Furthermore, the sensitivity of the method to assumptions about the pipeline design is examined, and the problems with using the combined wave and current induced velocity as a proxy for the response are discussed. The method is applied to a site in the Mediterranean Sea and the results are compared to those from the application of the first order reliability method.

This content is only available via PDF.
You do not currently have access to this content.