Environmental contours are used in structural reliability analysis of marine and coastal structures as an approximate means to locate the boundary of the distribution of environmental variables, and hence sets of environmental conditions giving rise to extreme structural loads and responses. Outline guidance concerning the application of environmental contour methods is given in recent design guidelines from many organisations.
Environmental contours are used in structural reliability analysis of marine and coastal structures as an approximate means to locate the boundary of the distribution of environmental variables, and to identify environmental conditions giving rise to extreme structural loads and responses. There are different approaches to estimating environmental contours, some directly linked to methods of structural reliability. Each contouring approach has its pros and cons. Although procedures for applying contours in design have been reported in articles and standards, there is still ambiguity about detail, and the practitioner has considerable flexibility in applying contours. It is not always clear how to estimate environmental contours well. Over four years, DNV-GL, Shell, the University of Oslo and HR Walling-ford worked together to review current practice regarding the use of design contours. In this paper, we present a summary of our findings. We overview the motivations for different approaches to contours, and their resulting characteristics. Using different marine applications, we also explore the various sources of uncertainty present, their impact on contour estimates and the estimation of extreme environmental loads and responses.
Avoiding accidents and ensuring the safety of on-board personnel represents one of the most complex challenges faced by the maritime industry. A common misunderstanding in the industry has led to a focus on occupational accidents to reduce lost time injuries in the belief that this would also lead to a reduction of major accidents. The complexity related to preventing and mitigating major accidents requires an understanding of the differences in occupational risk compared to major accident risk. An ever increasing complexity in systems and operations calls for increased vigilance with regards to safety. Rather than focusing on individual components, the industry would benefit by embracing a more comprehensive approach to safety, one that establishes effective barriers that prevent or mitigate the impact of accidents. The oil & gas industry has a long experience in handling complex operations and major accident hazards and offshore vessels can document significant lower incident rates than conventional merchant vessels. Introducing the concept of barrier management from the oil & gas industry to the maritime industry can provide the framework this industry needs to better manage major accident hazards.
The safe operation of any vessel is challenged by the constraints posed through design as well as maintenance and correct operation of the available safety barriers to ensure their effectiveness. This requires a direct linkage between barrier performance and operational risk management, accounting for potential degradation of the barriers and ensuing corrective actions. Therefore, the introduction of dynamic barrier management is a powerful tool in maintaining design resilience during operation and in emergencies. It is the purpose of this paper to demonstrate the achieved progress in developing a comprehensive approach to address risk in real-time. The authors aim to show how performance information on barrier elements and their respective functions is a) collated, b) aggregated through parametric (empirical) models for identifying barrier relative importance, function criticality and in defining a set of key safety indicators, and c) is intuitively visualized for providing real-time guidance to crew and shoreside management. The practicality of this approach is demonstrated by considering watertight doors as dynamic barriers preventing excessive transient-and progressive-flooding on a cruise vessel during operation. It will be discussed how these methods can be generalized into a framework, enabling operational risk management and subsequent decision support.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.