Concrete coated submarine pipelines: Further advances in strain concentration at field joints and relevant implications on strain based design
- Snamprogetti S.p.A., San Donato Milanese (Italy)
Recent projects in the North Sea stress the importance of the rationalization of design criteria for oil and gas submarine pipelines. From the review of relevant literature it appears that a key issue in this process is the introduction of strain based criteria, which have sometimes been advocated in the engineering practice. In particular, this is relevant to pipelay conditions which are a topical issue of the coming project scenarios. In fact, in some development projects the allowance for higher strains on the overbend or high usage factors on the sagbend of an ``S`` lay span, is in discussion these days. In these circumstances, the effect of the concrete coating, in terms of additional bending stiffness and strain concentration at field joints, may become very important. The scope of this paper is to investigate the flexural behavior of concrete coated pipes outside the linear elastic range. New advances in modelling the mechanical behavior of concrete coated joints are discussed. They account for the effect of the non linear stress-strain relationship of the steel at large usage factors/curvatures on the strain concentration at the field joint. An approach for the simulation of pipe string during laying and, hence, for the assessment of peak strains at field joint, is finally proposed. 27 refs., 20 figs., 2 tabs.
- OSTI ID:
- 160751
- Report Number(s):
- CONF-950501--
- Country of Publication:
- United States
- Language:
- English
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