Overturning Reliability Analysis of Jack-Up Platforms Using Spreadsheet

2013 ◽  
Author(s):  
Sirous F. Yasseri ◽  
R. B. Mahani
Keyword(s):  
Reliability Analysis ◽  
Conditional Probabilities ◽  
Safety Factors ◽  
Limit States ◽  
Environmental Loading ◽  
Environmental Loads ◽  
Structural Engineers ◽  
Jack Up

In designing jack-ups to resist environmental loading, decisions are made under a great deal of uncertainty that may lead to a finite risk of exceeding limit states of the structures. In order to minimize the risks, conventional safety factors based on deterministic analyses, are commonly used. This paper present a simple spreadsheet based reliability analysis for assessing the safety of independent leg jack up platforms subjected to the overturning effect of environmental loads. The intention is to develop and illustrate procedures that can be used by structural engineers to assign conditional probabilities of failure to jack ups as a function of environmental loads.

scholarly journals German Proposals for the Revision of Eurocode 7 “Geotechnical design”

2016 ◽  
Author(s):  
Markus Braun ◽  
Bernd Schuppener ◽  
Thomas Richter ◽  
Franz Ruppert ◽  
Martin Ziegler
Keyword(s):  
Human Error ◽  
First Generation ◽  
Safety Factors ◽  
Limit States ◽  
Eurocode 7 ◽  
Geotechnical Design ◽  
Partial Safety Factors ◽  
Structural Engineers ◽  
User Friendly ◽  
New Formula

After implementing the Eurocodes, concerns were raised that the set of rules and regulations is not suitable for the designer’s day-to-day use. The first generation of Eurocodes consists of 58 codes with more than 5,200 pages. Moreover, practitioners have to cope with national supplementary codes. As a result, an “Initiative on Improving the Practicability of Technical Rules for Building Constructions” (PRB) was established by the German construction industry and associations of structural engineers in 2011. As part of the initiative, a Project Group for Geotechnical Design was established alongside groups for the other Eurocodes, with the aim of streamlining Eurocode 7 and reducing the number of design approaches and partial safety factors. The paper will analyse the shortcomings of the two parts of Eurocode 7 and present a concept for a more concise and user-friendly code. Furthermore, comparative calculations have been performed for standard geotechnical design applications to investigate the potential for European harmonization in geotechnical design. The results are described and it is shown how they can be incorporated in the revision of EC 7. Moreover, a new formula for verifying geotechnical ultimate limit states is presented which formally covers all design approaches and also enables other parameters such as consequence classes, human error etc. to be incorporated by applying different multiplicative partial safety factors.

STRUCTURAL RELIABILITY ANALYSIS BASED ON P-BOXES

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Random Variable ◽  
Strength Criterion ◽  
Structural Elements ◽  
Structural Element ◽  
Limit States ◽  
Distribution Shape

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

Reliability analysis of wood I-joists

1993 ◽  
Vol 20 (4) ◽  
pp. 564-573 ◽  
Author(s):  
R. O. Foschi ◽  
F. Z. Yao
Keyword(s):  
Reliability Analysis ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Limit State ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Element Analysis ◽  
Strength Limit ◽  
Reliability Method ◽  
Load Carrying

This paper presents a reliability analysis of wood I-joists for both strength and serviceability limit states. Results are obtained from a finite element analysis coupled with a first-order reliability method. For the strength limit state of load-carrying capacity, multiple failure modes are considered, each involving the interaction of several random variables. Good agreement is achieved between the test results and the theoretical prediction of variability in load-carrying capacity. Finally, a procedure is given to obtain load-sharing adjustment factors applicable to repetitive member systems such as floors and flat roofs. Key words: reliability, limit state design, wood composites, I-joist, structural analysis.

scholarly journals Safety Standard for Special Class Damslopes Based on Reliability Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Lingzhi Huang ◽  
Zheng Si ◽  
Xiaoqi Du ◽  
Lifeng Wen ◽  
Bin Li
Keyword(s):  
High Risk ◽  
Reliability Analysis ◽  
Special Class ◽  
Slope Failure ◽  
Safety Margin ◽  
Class Ii ◽  
Class I ◽  
Safety Factors ◽  
Safety Standard ◽  
Risk Levels

The risk of slope failure is determined by the degree of damage caused by the slope slide. For the special-high slope of some high-risk water conservancy and hydropower projects, the standard should be appropriately raised. Thus, the safety standard for these slopes is explored on the basis of reliability analysis. The slopes with high risk of failure are divided into special class I and special class II slopes depending on the risk levels and acceptable risk standards. The concept of reliability theory-based relative ratio of the safety margin is utilized to establish the relationship between annual failure probability and safety factor, thereby obtaining the reasonable safety factors for different slopes. Results show that the values of safety factors for special class I and special class II are 1.40 and 1.35, respectively. These results can provide a reference for exploring the safety standards of dams with a height of more than 200 m.

Fatigue Safety Factors for Flexible Risers Based on Case Specific Reliability Analysis

2005 ◽  
Author(s):  
Bernt J. Leira ◽  
Ragnar T. Igland ◽  
Gro S. Baarholm ◽  
Knut A. Farnes ◽  
Dick Percy
Keyword(s):  
Reliability Analysis ◽  
Limit State ◽  
State Function ◽  
Safety Factors ◽  
Fatigue Lifetime ◽  
Statistical Variation ◽  
Parametric Studies ◽  
Flexible Risers ◽  
Corrosive Environments ◽  
Wave Induced

In the present paper, fatigue safety factors for flexible risers are assessed. A procedure for reliability analysis of wave-induced fatigue is first described. The procedure is based on performing a number of parametric studies with respect to variables that influence the fatigue lifetime. The results of these parametric studies are subsequently combined with models describing the statistical scatter of the same parameters. By application of this procedure, the safety factors which are required in order to reach specific target reliability levels can be computed. Such safety factors are computed for three specific flexible riser configurations. Different SN -curves which correspond to different corrosive environments are considered. The percentwise contribution from each parameter to the total statistical variation of the limit state function is also quantified.

Safety factors and limit states analysis in geotechnical engineering

1984 ◽  
Vol 21 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. G. Meyerhof
Keyword(s):  
Geotechnical Engineering ◽  
Stability Conditions ◽  
Safety Factors ◽  
Limit States ◽  
Resistance Factors ◽  
Performance Factors ◽  
Load Factors ◽  
Partial Safety Factors ◽  
And Performance ◽  
Earth Retaining Structures

This paper outlines the ultimate and serviceability limit states in geotechnical engineering analyses. The magnitude of customary total and suggested partial safety factors in earthworks, earth retaining structures, excavations, and foundations is discussed. On the basis of comparisons between these safety factors and using recommended load factors on various types of loading, including water pressures, common resistance factors on cohesion and friction of soils and performance factors can be established together with some additional modification factors for particular stability conditions. The serviceability limit states of foundations and structures are briefly discussed.

Recent developments in timber engineering

1983 ◽  
Vol 10 (4) ◽  
pp. 722-739
Author(s):  
Borg Madsen ◽  
Robert Sexsmith
Keyword(s):  
Structural Design ◽  
Design Standards ◽  
Limit States ◽  
Design Engineers ◽  
Major Scale ◽  
Recent Developments ◽  
The Subject ◽  
Structural Engineers ◽  
Timber Engineering

Wood is one of the world's most commonly used structural materials, but structural engineers do not become involved with it as often as with steel and concrete. They can, however, do so on a major scale, as there are very important structures of engineered wood. Structural design in wood is therefore of interest to designers; it is covered by several design standards and is the subject of research in many universities and government sponsored institutions in Canada and elsewhere.This discussion is directed to practicing design engineers seeking knowledge regarding structural design and behaviour in wood but who are not deeply involved with research or code development. It is intended as an up-date to illustrate the role of wood in structures, recent improvements in understanding its behaviour, and trends in design standards as they move to the limit states design format.

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