The influence of tension, pressure, and weight on different aspects of pipe and riser behavior has already been the subject of many articles (see references). In spite of this it has frequently been misunderstood, sometimes with serious consequences. The object of this paper is to explain the subject clearly and the approach is therefore deliberately very elementary. The principal problems of bending, buckling, yielding and strains, usually treated in separated papers, are here treated homogeneously. The widely used concepts of “effective tension” and “effective stress” are given interpretations, easy to visualise, which are related to analogous concepts in other engineering fields. Finally, eight diverse particular examples of the influence of tension, pressure and weight on pipe and riser behavior, are discussed.

ABSTRACfThis paper presents results of a Joint Industry Program (I.J.P.) to qualify high performance composite tubes, made from carbon fibres/glass fibres and resin, for use as individual TLP production rIsers. The program covered the design, fabrication and testing of six samples of composite tube (9"1.0.) for such an application. It was conducted by the INSTITUT FRANCAIS DU PETROLE between 1985-1987 and was supported nine other organisations (see Acknowledgements).

Résumé -Vibrations transverses modales de risers verticaux tendus. Approche analytique simplifiée -Le présent article est consacré à l'analyse structurelle des vibrations transverses modales d'un riser vertical tendu. Ces vibrations, souvent de type VIV (Vortex Induced Vibrations), apparaissent en présence d'un courant lorsque la fréquence des lâchers tourbillonnaires coïncide avec une des fréquences propres de la structure. Une approche analytique simplifiée est proposée pour le cas d'un riser possédant des caractéristiques de poids apparent et de masse linéique uniformes. Des formules très simples sont ainsi obtenues pour les paramètres structurels les plus significatifs : fréquences propres, positions des noeuds et des ventres, débattements angulaires en tête et en pied, valeurs et positions des points de courbure maximale. Les formules obtenues permettent de mieux comprendre la réponse structurelle d'un riser en eau profonde en condition dite « d'accrochage », pour le phénomène de VIV.