scholarly journals Conception and Evolution of the Probabilistic Methods for Ship Damage Stability and Flooding Risk Assessment

2021 ◽  
Vol 9 (6) ◽  
pp. 667
Author(s):  
Dracos Vassalos ◽  
M. P. Mujeeb-Ahmed
Keyword(s):  
Risk Assessment ◽  
Probabilistic Method ◽  
Probabilistic Methods ◽  
Full Description ◽  
Safety Level ◽  
Probability Of Survival ◽  
Damage Stability ◽  
Passenger Ships ◽  
Flooding Hazards ◽  
Flooding Risk

The paper provides a full description and explanation of the probabilistic method for ship damage stability assessment from its conception to date with focus on the probability of survival (s-factor), explaining pertinent assumptions and limitations and describing its evolution for specific application to passenger ships, using contemporary numerical and experimental tools and data. It also provides comparisons in results between statistical and direct approaches and makes recommendations on how these can be reconciled with better understanding of the implicit assumptions in the approach for use in ship design and operation. Evolution over the latter years to support pertinent regulatory developments relating to flooding risk (safety level) assessment as well as research in this direction with a focus on passenger ships, have created a new focus that combines all flooding hazards (collision, bottom and side groundings) to assess potential loss of life as a means of guiding further research and developments on damage stability for this ship type. The paper concludes by providing recommendations on the way forward for ship damage stability and flooding risk assessment.

Small Ro/Pax Vessel Stability Study

2015 ◽  
Author(s):  
Henrik Erichsen ◽  
Hans Kristensen ◽  
Jørgen Jensen ◽  
Erik I. Tvedt
Keyword(s):  
Probabilistic Method ◽  
Stability Study ◽  
Safety Level ◽  
Small Vessels ◽  
Damage Stability ◽  
Passenger Ships ◽  
Solid Foundation ◽  
Vessel Stability ◽  
Very High

In 2009 new damage stability requirements for passenger ships based on a probabilistic method were adopted by IMO and are now part of the current SOLAS Chapter II-1 regulations (SOLAS 2009). The mandate from IMO was to keep the same safety level as inherent in the old deterministic damage stability regulations in SOLAS (SOLAS 90). During the rule development prior to the adoption, it was argued that the safety level for large passenger ships should be increased, but small ro/pax vessels were only rudimentarily looked at and small vessels with very high attained index were seen as “non-representative”. Currently there is a renewed debate in IMO regarding the required damage stability safety level for passenger ships. The damage stability safety level for small ro/pax vessels has also been discussed outside of the IMO assuming that the damage stability safety level for small ro/pax designs is perhaps not sufficient, i.e. that the current safety level according to SOLAS 2009 is less than the old safety level according to SOLAS 90. In order to establish a solid foundation for the discussion, this study was made possible by a grant from The Danish Maritime Fund. The study focus on small ro/pax vessels in a range from 32 m to 100 m in length and 100 to 600 passengers/persons, and the outcome of this study is described in details in this document.

A Performance-Based Assessment of the Survival of Damaged Ships: Final Outcome of the EU Research Project HARDER

2003 ◽  
Vol 40 (04) ◽  
pp. 288-295
Author(s):  
Robert Tagg ◽  
Cantekin Tuzcu
Keyword(s):  
Model Test ◽  
Research Project ◽  
Additional Function ◽  
Probability Of Survival ◽  
Damage Stability ◽  
Passenger Ships ◽  
Performance Based Assessment ◽  
The 1960S ◽  
Equivalent Method ◽  
The Eu

The paper presents the results of the EU Research Project HARDER with regard to the development of generalized formulations to predict the probability of survival of a damaged ship in a seaway. The methodology follows the procedures used to develop the survivability functions for the probabilistic damage stability regulations for passenger ships developed in the 1960s but makes use of an extensive series of a new model test carried out both as part of the HARDER Project and as part of independent external model tests. Simplified formulations based on static calculations have been proposed and correlated to the model test results. Two formulations are proposed, one to be applied to all types of ships, and an additional function based on the static equivalent method (SEM) methodology, which is suitable for roll-on/roll-off (RO/RO) ships (or any other ships with large unsubdivided horizontal spaces near the final damaged waterline). These formulas are currently under consideration by the International Maritime Organization (IMO) for the new harmonized damaged stability regulations in the upcoming SOLAS 2006 revisions.

Actual Problems of the Safety and Reliability of the NPP Structures in Slovakia

2017 ◽  
Vol 738 ◽  
pp. 261-272 ◽  
Author(s):  
Juraj Kralik
Keyword(s):  
Risk Assessment ◽  
Numerical Methods ◽  
Probabilistic Analysis ◽  
Material Model ◽  
Safety Level ◽  
Concrete Cracking ◽  
The World ◽  
Safety And Reliability ◽  
Long Time ◽  
Calculated Model

The last accidents of the NPP in Chernobyl and Fukushima give us the new inspiration to verify the safety level of the NPP structures. This paper presents the new requirements to test of the safety and reliability of the NPP structures due to the last accidents in the world. The risk assessment to verify of the safety and reliability of the NPP structures based on probabilistic and nonlinear analysis is presented. The uncertainties of the loads level (long-time temperature and dead loads), the material model (concrete cracking and crushing, behaviour of the reinforcement and liner), degradation effects and other influences following from the inaccuracy of the calculated model and numerical methods were taken into account in the LHS method. The results of the deterministic and probabilistic analysis of the NPP structures are presented.

Guidance for Human Action Evaluations for External Flood Risk Assessment

2016 ◽  
Author(s):  
Raymond E. Schneider ◽  
Srinivasa Visweswaran ◽  
John Fluehr ◽  
H. Alan Hackerott
Keyword(s):  
Risk Assessment ◽  
Ad Hoc ◽  
Human Action ◽  
Mitigation Strategies ◽  
Flood Mitigation ◽  
Human Reliability Analysis ◽  
Factors Affecting ◽  
Investment Protection ◽  
Performance Shaping Factors ◽  
Flooding Hazards

For many years external flooding hazards have been recognized as significant contributors to plant risk. However, it was not until the events at Fukushima that there was a concerted effort on the part of the utilities to reassess the plant external flood design basis, identify external flood vulnerabilities and take actions to address them. For many plants, resolution of low probability high consequence floods will likely be addressed by a combination of actions involving enhancements to flood protection and hazard mitigation strategies. Over time, as plants decide on which strategies to apply there is an expectation that the most effective way to develop and justify these strategies will involve probabilistic risk assessment (PRA) concepts. The PRA framework is well suited for performing a human reliability analysis (HRA). Within that framework, HRA evaluations focus on operator and plant staff actions taken in response to plant initiating events (e.g., loss of offsite power, etc.). For many external floods, advance warning of an impending external flood event provides the trigger for pre-emptive manual actions to potentially reconfigure the plant through temporary installation of flood barriers. Unlike the post-initiator actions which tend to be more narrowly focused, these pre-emptive actions are taken in a less controlled environment, may be ad hoc, and may potentially be in competition with site investment protection activities, site evacuation, etc. The purpose of this paper is to define the challenges in defining an approach for treating external flood actions, identifying external flood timelines, identifying the manual actions/organizational environment during external flooding scenarios and proposing an integrated strategy for quantifying those actions. The proposed quantification process is rooted in management science concepts for evaluating project reliability. The overall methodology identifies flood significant performance shaping factors, and identifies three (3) factors, namely time available for flood mitigation, proper access to plant site following flood and environmental factors, as having an overarching impact on the performance shaping factors affecting each of the flood mitigation tasks.

Survival Criteria for Passenger Roll-On/Roll-Off Vessels and Survival Time

2007 ◽  
Vol 44 (01) ◽  
pp. 27-34
Author(s):  
Maciej Pawtowski
Keyword(s):  
Survival Time ◽  
No Value ◽  
Large Scale ◽  
Direct Link ◽  
Stability Criteria ◽  
Damage Stability ◽  
Passenger Ships ◽  
S Factor ◽  
Control Decision ◽  
Time To Capsize

The paper addresses the problem of damage stability criteria with reference to survival time, that is, the time available for evacuation of passengers on a damaged passenger roll-on/roll-off (RO/RO) vessel undergoing large-scale flooding on the car deck. The current various proposals at the International Maritime Organization (IMO) for the s factor (probability of surviving a given flooding) make no reference to survival time. The paper shows a direct link of the "prime" s factor with the time to capsize. This link has unprecedented value for a flooding control decision support system used during a crisis on board passenger ships but is of no value for the designer for whom the s factor means simply probability of surviving with adequate survival time. The paper shows how to utilize experimental data from 30-minute test runs for survival criteria based on longer duration of tests.

scholarly journals Probabilistic methods for risk assessment of anthropogenic accidents and emergency

2019 ◽  
Vol 20 ◽  
pp. 136-142
Author(s):  
Ulyana S. Ivanova ◽  
Olga V. Taseiko ◽  
Daria A. Chernykh
Keyword(s):  
Risk Assessment ◽  
Probabilistic Methods

Probabilistic Structural Analysis of Railroad Subgrade Using Finite Element Analysis

2019 ◽  
Author(s):  
Asif Arshid ◽  
Ying Huang ◽  
Denver Tolliver
Keyword(s):  
Finite Element ◽  
Structural Analysis ◽  
Shear Failure ◽  
Probabilistic Method ◽  
Probabilistic Methods ◽  
Influential Factor ◽  
Element Analysis ◽  
3 Dimensional ◽  
Weather Changes ◽  
Granular Layers

The reliability of finite element (FE) based deterministic structural analysis of railroad trackbed has improved significantly due to ever increasing computational powers. However, the application of probabilistic methods to incorporate the material and geometric variabilities in these FE analyses is still profoundly underworked. In this study, the influence of variability in granular layers’ modulus and thicknesses values on the railroad subgrade performance have been investigated by applying probabilistic method and using a 3-dimensional FE based numerical trackbed model previously developed and validated by the authors’ research group. The influence of these factors is accounted for by changing their coefficients of variance (COV) while keeping their means constant. Preliminary results revealed that the variation in subgrade modulus is the most influential factor for subgrade performance, both in terms of progressive shear failure and excessive plastic deformations, followed by ballast modulus. Variations in depths, for the range studied, remained passive to the subgrade performance. The findings of this work is of particular significance in evaluating the subgrade performance while including the material and geometric variations, which may be caused by construction imperfections, weather changes, and/or rail operations.

scholarly journals On the alternative approaches to stability analysis in decision support for damaged passenger ships

2019 ◽  
Vol 18 (3) ◽  
pp. 477-494 ◽  
Author(s):  
Pekka Ruponen ◽  
Petri Pennanen ◽  
Teemu Manderbacka
Keyword(s):  
Decision Support ◽  
Stability Analysis ◽  
Decision Support System ◽  
Support System ◽  
Point Of View ◽  
Additional Information ◽  
Damage Stability ◽  
Passenger Ships ◽  
Minimum Requirements ◽  
The Stability

Abstract A decision support system with damage stability analysis has been recognized as an important tool for passenger ships. Various software applications have been developed and taken into use over the years, without a direct link to any compelling requirement, set forth in the international regulatory framework. After the Costa Concordia accident, new regulations have been established, setting minimum requirements for a decision support system, as an extension to a loading computer. Yet, more advanced systems have been developed recently, aiming at providing valuable additional information on the predicted development of the stability of the damaged ship. This paper presents these alternative decision support systems with damage stability analysis methods for flooding emergencies on passenger ships. The technical background, usability, and usefulness of the various approaches are compared and discussed, taking into account the important statutory approval point of view. In addition, practical examples, including past accidents, are presented and discussed.

scholarly journals Reconfiguring Passenger Ship Internal Environment for Damage Stability Enhancement

2020 ◽  
Vol 8 (9) ◽  
pp. 693
Author(s):  
Dracos Vassalos ◽  
Donald Paterson
Keyword(s):  
Cost Effective ◽  
New Normal ◽  
Stability Margins ◽  
Physical Limit ◽  
Damage Stability ◽  
Damage Limitation ◽  
Technological Developments ◽  
Flooding Risk ◽  
Internal Arrangement ◽  
The 19Th Century

The traditional risk control option adopted in naval architecture to meet safety-related objectives is by regulations, targeting damage limitation, nominally instigated in the wake of maritime accidents claiming heavy loss of life. These primarily concern the introduction of watertight bulkheads, i.e., permanent (passive) reconfiguration of the internal ship environment to enhance damage stability. This has been the most common measure, manifesting itself in the wake of every serious flooding accident since the beginning, back in the 19th century. However, traditional flooding protection through watertight subdivision, to an extent dictated by IMO regulations, has a physical limit which, if exceeded, a safety plateau is reached. This is currently the case and with damage stability standards progressively increasing, the safety gap between existing and new ships is dangerously widening and with design stability margins progressively eroding, stability management is unsustainable, leading to loss of earnings at best. The need for managing the residual risk through active intervention/protection over the life-cycle of the vessel drives industry to searching and adopting a new normal. This new normal is the innovation being explained in this paper by addressing safety enchantment through a systematic reconfiguration of the ship environment for passive and active protection in flooding accidents. In this respect, the “design-optimal” internal arrangement of a vessel, is adapted and reconfigured, using passive and active containment systems for flooding incidents, in the form of high-expansion foam products. The innovation is briefly explained, claiming transformational reduction in flooding risk in the most cost-effective way available. To support wider understanding and appreciation for the latter, the paper critically reviews the whole evolution of internal ship space reconfiguration, chronologically and systematically, concluding that new technological developments and breakthroughs will bring sustainable changes to the traditional evolutionary maritime safety enhancement.

scholarly journals Application of Probabilistic Method to Stability Analysis of Gravity Dam Foundation over Multiple Sliding Planes

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Gang Wang ◽  
Zhenyue Ma
Keyword(s):  
Probabilistic Method ◽  
Complex Problem ◽  
Probabilistic Methods ◽  
Gravity Dam ◽  
Engineering Profession ◽  
Concrete Gravity Dam ◽  
Dam Foundation ◽  
Performance Function ◽  
Probability Calculation ◽  
Implicit Performance Function

The current challenge to the engineering profession is to carry out probabilistic methods in practice. The design point method in generalized random space (DPG method) associated with the method of divided difference can be utilized to deal with the complex problem of probability calculation of implicit performance function with nonnormal and correlated variables. For a practical concrete gravity dam, the suggested method is performed to calculate the instability probability of the dam foundation over multiple sliding places. The general conclusions drawn in the paper are identical to those in other research and the method is proved to be feasible, accurate, and efficient. As the same analysis principle, the method can also be used in other similar fields, such as in fields of slopes, earth-rock dams, levees, and embankments.

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