scope:

The scope of this document is to provide rational design criteria and guidance for assessment of dynamic response of pipeline free spans due to combined wave and current loading. Detailed design criteria are specified for ultimate limit state (ULS) and fatigue limit state (FLS) due to in-line and cross-flow vortex induced vibrations (VIV) and direct wave loading.

Free span design may be performed by conservative avoidance criteria, simplified fatigue criteria or detailed fatigue analyses, all of which are covered in this RP. Whenever fatigue is allowed in design, extreme environmental events may cause loading on the structure which, in case, must be accounted for in ULS design, and detailed guidance for how to include contributions to ULS calculations due to environmental loading is also provided in this RP.