Recent studies on the behavior of the simple free-hanging configuration for flexible risers have shown that, for very deepwater levels, they are reaching their technical and economic limits. Other alternative configurations are currently being investigated, including hybrid riser configurations based on flexible jumpers connected to an intermediate point closer to the free surface (usually a submerged buoy). This work focuses on the jumper issue, considering that, since it is completely suspended, its behavior may differ significantly from the behavior of a riser resting on the seabed. Therefore, the usual design procedure employed for conventional applications may not be completely adequate, and should be complemented by alternative approaches. This work considers analytical, numerical, and experimental approaches for the design of flexible jumpers. First, a comprehensive static analysis using consistent catenary concepts is developed; this results in criteria that are essential for safe design. Subsequently, a modal analysis procedure is described; this procedure considers the nonlinear behavior of the jumpers under the static component of the environmental loads, and may show the existence of resonant modes that require careful consideration. This defines the importance of damping mechanisms, and orients parametric time-domain nonlinear verifications. Finally, reduced model tests are considered, devised specifically to investigate the jumper behavior under centenary conditions. The design of the physical model and the similarity analysis of the experimental results are also presented.

Fernandes, A. C., Jacob, B. P., Silva, R. M. C., Carvalho, R. A., and Lemos, C. A. O., 1999, “Design of Flexible Jumpers for Deepwater Hybrid Riser Configurations,” XVIII International Conference on Offshore Mechanics and Arctic Engineering (OMAE), St. John’s, Canada.
Serta˜, O. B., Fernandes, A. C., Pinto, F. J. C., 1997, “Consolidated Concepts for Deep Water Steel Catenary Design: Summary of a PETROBRAS Workshop,” Deep Offshore Technology Conference, DOT 1997, The Hague, Netherlands.
DeepStar, 1994, “Production Riser, Buoy Design and Installation Study,” I, Main Report, DSII CTR 420-1; Aker Omega, June.
Bouygues Offshore, 1998, “Girassol Field,” presented in PETROBRAS, Rio de Janeiro.
DeepStar, 1996, “Deepwater Hybrid Riser Study,” Doc. No.: 1085-RPT-0002 Rev:03, DSIII CTR 3401-1;2H Offshore Eng. Ltd., Nov.
Fernandes, A. C., 1997, “Up-to-date Spread-Sheet Program For Preliminary Analysis Of Flexible And Steel Catenary Risers Using Catenary Concepts,” X International Symposium on Offshore Engineering (Brasil Offshore), Rio de Janeiro, RJ, September 3–5.
Carvalho, R. A., and Fernandes, A. C., 1998, BoiSub1.xls—Microsoft Excel 5.0 Spreadsheet, Rio de Janeiro.
Bathe, K. J., 1996, Finite Elements Procedures, Prentice-Hall, Englewood Cliffs, NJ.
Mourelle, M. M., Gonzalez, E. C. and Jacob, B. P., 1995, “ANFLEX-Computational System for Flexible and Rigid Riser Analysis,” eds., F. L. L. B. Carneiro et al., International Offshore Engineering, John Wiley & Sons, Chichester/New York, pp. 441–458.
Nour-Omid, B., 1987, “The Lanczos Algorithm for Solution of Large Generalized Eigenproblems,” ed., T. J. R. Hughes, The Finite Element Method—Linear Static and Dynamic Finite Element Analysis, Prentice-Hall, Englewood Cliffs, NJ, pp. 582–630.
Orcina, 1998, Visual Orcaflex User Manual—Design Software for Flexible Risers and Offshore Systems, Orcina Limited, UK.
Nyholm-Larsen, H., Gregersen, J. R., and Mathinsen, F., 1998, “Air Suspended Flowline Between Platforms,” XVII International Conference on Offshore Mechanics and Arctic Engineering (OMAE), Lisbon, Portugal.
da Silva, S., 1999, “Ensaio em Ondas de Modelo da Bo´ia Submersa para Suporte de Risers de Produc¸a˜o” (in Portuguese), IPT Report 39994 to COPPETEC, Sa˜o Paulo, July.
Fernandes, A. C., Mourelle, M. M., Serta˜, O. B., Parra, P. H. C. C., and da Silva, S., 1997, “Hydrodynamic Coefficients in the Design of Steel Catenary Risers,” XVI International Conference on Offshore Mechanics and Arctic Engineering (OMAE), Yokohama, Japan.
You do not currently have access to this content.