Hybrid Subsea Foundations for Subsea Equipment
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 139, Issue 12
Abstract
A hybrid subsea foundation (HSF) is defined here as the combination of shallow and deep foundations, designed such that both shallow and deep foundation elements contribute to the total foundation capacity. In this project the type of HSF investigated is a shallow mat foundation connected to short piles, with pinned connections made close to the mat corners. The motivation for this research is the potential economic benefit to using HSFs in deepwater subsea developments, where mat sizes to resist typical subsea foundation design loads (e.g., from pipeline end terminations, manifolds, and riser bases) require ever larger installation vessels with higher associated cost. This paper assesses the design feasibility of a HSF for subsea facilities in soft clay and provides recommendations for design. The focus here is on analytical and numerical modeling, although corroborating results from physical modeling are provided. Numerical and physical modeling has shown that the proposed analytically based design approach is suitably conservative, with deformations well within typical serviceability limits at the calculated capacities. Most significantly, the paper demonstrates that significant reduction in the foundation footprint can be realized by supplementing a mat with short piles at each corner.
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Acknowledgments
The authors thank BP Exploration for permission to publish this work. The work also forms part of the activities of the Centre for Offshore Foundation Systems (COFS), currently supported as a node of the Australian Research Council Centre of Excellence for Geotechnical Science and Engineering, and by The Lloyd’s Register Educational Trust.
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Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 139 • Issue 12 • December 2013
Pages: 2182 - 2192
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Sep 17, 2012
Accepted: Apr 8, 2013
Published online: Apr 10, 2013
Published in print: Dec 1, 2013
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