Risk Assessment and Management for Geotechnical Design of Offshore Installations
- Suzanne Lacasse (NGI Oslo) | Farrokh Nadim (NGI Oslo) | Noel Boylan (NGI Perth) | Zhongqiang Liu (NGI Oslo) | Young Jae Choi (NGI Houston)
- Document ID
- Offshore Technology Conference
- Offshore Technology Conference, 6-9 May, Houston, Texas
- Publication Date
- Document Type
- Conference Paper
- 2019. Offshore Technology Conference
- 4 Facilities Design, Construction and Operation, 7.2.1 Risk, Uncertainty and Risk Assessment, 7 Management and Information, 4.5.5 Installation Equipment and Techniques, 4.5 Offshore Facilities and Subsea Systems, 4.2 Pipelines, Flowlines and Risers, 5.6.3 Deterministic Methods, 7.2 Risk Management and Decision-Making
- risk, hazard, Geotechnical design, uncertainties, reliability
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More than before, society and standards require "risk-informed" decision-making. The paper demonstrates the benefits of implementing reliability concepts in offshore geotechnical design. Reliability-based approaches will assist preparing engineering recommendations and decision-making. The paper gives an overview of basic concepts of reliability-based design, discusses the advances of hazard, risk and reliability in geotechnical engineering and illustrates their use with case studies from offshore practice. Risk and reliability evaluations can vary from simple statistical evaluations to full probabilistic modelling of the hazards and consequences for a single or a system of offshore installations. The examples include pipeline siting, jack-up mobile units, piled foundations and the reliability of code requirements. The paper discusses the strengths of the reliability-based approach and key issues such as tolerable and acceptable risk and the selection of characteristic value. The paper concludes that reliability-based approaches offer a useful complement to deterministic analyses, and enable analyzing complex situations with uncertainties in a systematic and more complete manner than deterministic analyses alone, both for design and for reevaluation. Managing geotechnical risks should today become a natural part of the engineer's work.
|File Size||2 MB||Number of Pages||35|
Becker, D.E. (1996a). Eighteenth Canadian Geotechnical Colloquium: Limit States Design for Foundations. Part I. An overview of the foundation design process. Canadian Geotechnical Journal, 1996, 33(6): 956-983, 10.1139/t96-124.
Lacasse, S., Liu, Z.Q. and Nadim, F. (2017). Probabilistic Characterization of Soil Properties – Recognition of Wilson Tang's Contribution to Geotechnical Practice. In C.H. Juang. (Eds.), GeoRisk 2017. Geotechnical Safety and Reliability: Honoring Wilson H. Tang. Geotechnical Special Publication 286 (pp. 2-26). ASCE.
Becker, D.E. (1996b). Eighteenth Canadian Geotechnical Colloquium: Limit States Design for Foundations. Part II. Development for the National Building Code of Canada. Canadian Geotechnical Journal, 1996, 33(6): 984-1007, 10.1139/t96-125.
Chen, J.B, Gilbert, R.B., Choo, Y.S., Marshall,.W. and Murff, J.D. (2016). Two-Dimensional Lower Bound Analysis of Offshore Pile Foundation Systems. International Journal for Numerical and Analytical Methods in Geomechanics 40 (9): 321–1338. doi: 10.1002/nag.2488.
Li, J.H., Hu, P., Uzielli, M., and Cassidy, M.J. (2017). Bayesian prediction of peak resistance of a spudcan penetrating sand-over-clay Géotechnique 68, No. 10, 905–917 [https://doi.org/10.1680/jgeot.17.P.154]
Chen, J. and Gilbert, R.B. (2017). Offshore pile system model biases and reliability, Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 11:1, 55-69, DOI: 10.1080/17499518.2016.1250914.
Christian J.T. and Baecher G.B. (2011). Unresolved Problems in Geotechnical Risk and Reliability. State-of-the-Art. ASCE Georisk 2011. Atlanta PA. USA. https://doi.org/10.1061/41183(418)3
Nadim, F. (2015). Accounting for Uncertainty and Variability in Geotechical Characterization of Offshore Soils. ISGSR 2015: Geotechnical Safety and Risk V. Proc. Schweckendiek (eds.) (23-34). IOS Press. DOI: 10.3233/978-1-61499-580-7-23.
ISO Guide 73:2009. Risk management – Vocabulary (https://www.iso.org/obp/ui/#iso:std:iso:guide: 73: ed-1:v1:en).
Schneider, H.R. and Schneider, M.A. (2013). Dealing with uncertainties in EC7 with emphasis on the determination of characteristic soil properties. In Modern Geotechnical Design Codes of Practice. Arnold, P., Fenton, G.A., Hicks, M.A. and Schweckendick, T (eds). IOS Press, Rotterdam The Netherlands, pp. 87-101.
Simpson, B. (2014). Eurocode 7 - Good practice in geotechnical design. The 8th Lumb Lecture. The University of Hong Kong. Nov.2014. http://www.civil.hku.hk/contents/content_h4d_10.htm
ISSMGE (2004). Glossary of Risk Assessment Terms (http://220.127.116.11/issmge/2004Glossary_Draft1.pdf):
USACE (2011). US Army Corps of Engineers. Engineering and Design. Safety of Dams – Policy and Procedures. Engineer Regulation ER 1110-2-1156. Washington DC: USACE. http://publications.usace.army.mil/publications/eng-regs/ER_1110-21156/ER_1110-2-1156.pdf.
US Bureau of Reclamation (2011). Dam Safety Public Protection Guidelines. Dam Safety Office, Denver, Colorado. August. Web site: (http://www.usbr.gov/ssle/damsafety/documents/PPG201108.pdf).