L52286 Limit State Function Development for the Application of RBD and Assessment to Onshore Pipelines

For pipelines that utilize high design factors, excessive plastic deformation may occur in the hoop direction under internal pressure applied during field hydrostatic testing. Excessive plastic deformation can lead to coating damage and subsequent corrosion. Therefore, a limit state function for excessive plastic deformation was established to address this condition. The limit state function was established as the allowable plastic strain minus the accumulated plastic hoop strain induced by hydrostatic test pressure.

The objective of this study was to expand the limit state function library to allow a wider range of conditions and threats to be explicitly considered in the application of RBDA. The new limit state functions developed in this study are applicable to situations involving excessive plastic deformation under hydrostatic testing pressure, restrained thermal expansion, seam-weld defects and stress-corrosion cracking (SCC). The basic assumptions and methodologies used to develop these limit state functions are described in this report. Probabilistic characteristics of the input parameters (including model uncertainties) associated with each limit state function are also summarized based on publicly available literature, studies funded by PRCI and data provided by PRCI members.