Limit-state design of high-temperature pipelines
- Shell Research B.V., Rijswijk (Netherlands)
- SAIC Science and Engineering Ltd., London (United Kingdom). Artillery House
- Univ. of Texas, Austin, TX (United States). Dept. of Aerospace Engineering and Engineering Mechanics
As pipelines and flow lines operate at higher temperatures, it becomes increasingly difficult to meet the conventional design criteria formulated in terms of limits on the hoop stress and the equivalent stress. For temperatures above, say, 80 C, the equivalent stress criterion will govern and will lead to pipes which are very thick-walled and require high soil or rock cover to avoid upheaval buckling. For temperatures above 100 C this may result in very unsatisfactory designs, both from an economic and a safety point of view. Excessive wall thicknesses can be avoided by use of limit state design concepts. This paper deals with the particular case of a pipeline which is trenched, buried or anchored, and therefore fully constrained, and operates at high temperature. The failure modes (limit states) that are relevant for such a pipeline are identified and analyzed in some detail. It is demonstrated that cyclic ratcheting during start-up and shut in/shut-down cycles places the most stringent limits on the allowable loading, and this forms the basis of a new strain based design method in which the usual limit on equivalent stress is replaced by a limit on allowable design temperature; the safety and cost implications of this new approach are highlighted. The new method permits safe, economic design of pipelines operating at higher temperatures (up to, say, 200 C). The proposed method is permitted by several codes.
- OSTI ID:
- 55743
- Report Number(s):
- CONF-940230-; ISBN 0-7918-1268-5; TRN: IM9525%%424
- Resource Relation:
- Conference: 13. international conference on offshore mechanics and Arctic engineering (OMAE-13), Houston, TX (United States), 27 Feb - 3 Mar 1994; Other Information: PBD: 1994; Related Information: Is Part Of OMAE 1994. Volume 5: Pipeline technology; Murray, A.; Fernandez, M.L.; Thygesen, J.E. [eds.]; PB: 373 p.
- Country of Publication:
- United States
- Language:
- English
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