SEDL / STP / STP1137-EB / STP19762S

A Theoretical Analysis for the Residual Strength of Corroded Gas and Oil Transmission Pipelines

Kanninen, MF
program director, Engineering Mechanicssenior research engineerprofessor, The Southwest Research InstituteThe Ohio State University, San AntonioColumbus, Ohio

Pagalthivarthi, KV
program director, Engineering Mechanicssenior research engineerprofessor, The Southwest Research InstituteThe Ohio State University, San AntonioColumbus, Ohio

Popelar, CH
program director, Engineering Mechanicssenior research engineerprofessor, The Southwest Research InstituteThe Ohio State University, San AntonioColumbus, Ohio

Pages: 16    Published: Jan 1992

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Abstract

The current regulations governing the integrity of corroded gas and oil pipelines are empirical. In many cases the guidelines are very conservative, but even so they are not reliably conservative in all instances. To improve upon this situation, a theoretical approach was taken within elastic shell bending theory. Preliminary results developed using a maximum hoop stress criterion in an axisymmetric approximation of the metal loss provided a relation for the failure pressure for a pipe with axial direction metal loss. It was found that the form assumed in the existing empirical approach is essentially correct in so far as the axial extent of the damage governs. However, the extension of the shell bending theory approach to the plane strain case indicates that it may be the circumferential dimension of the damage that actually governs the failures of corroded pipes. While this important finding must be confirmed by further analyses and experimentation, this result indicates the usefulness of the type of approach described in this paper. The use of even simple mechanics models where only empirical approaches currently exist can surely be useful to address corrosion-related problems associated with a variety of infrastructural components.