Calibration basis for structural glass design

1987 ◽  
Vol 14 (6) ◽  
pp. 788-794
Author(s):  
Niels C. Lind
Keyword(s):  
Reliability Index ◽  
Limit State ◽  
Structural Response ◽  
Economic Cost ◽  
Structural Glass ◽  
Safety Level ◽  
Design Standard ◽  
Code Calibration ◽  
Importance Factor ◽  
Selection Of

A design standard for structural glass in the limit state design format is currently being developed under the auspices of the Canadian General Standards Board. The standard will be calibrated to a target level of reliability expressed in terms of a reliability index. The selection of this reliability level presents some special problems because the loading is dynamic, the structural response is geometrically nonlinear, and the strength is highly dependent on time, size, and loading history. Selection of safety level so as to achieve a social and economic optimum is described. The optimum reliability index is 3.0, corresponding to a lifetime failure probability of 0.0014, when the social and economic cost of failure is between 15 and 70 times the initial cost. Optimal ranges of applicability over cost for a pair of importance factors (0.8 and 1.25) are also determined. Key words: glass, design, standard, code, calibration, reliability, optimization, importance factor.

Practical code calibration procedures

1979 ◽  
Vol 6 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Andrzej S. Nowak ◽  
Niels C. Lind
Keyword(s):  
Probability Distributions ◽  
Design Standards ◽  
Limit States ◽  
Safety Level ◽  
Performance Factors ◽  
Code Calibration ◽  
Earthquake Load ◽  
Load Effects ◽  
Safety Indices ◽  
Selection Of

The paper deals with a procedure that can be used by a design standards committee to determine safety indices for structures and calculate optimum performance factors for limit states design. Six load components are considered: dead, sustained live, transient live, snow, wind, and earthquake load effects. The procedure is based on an approximation of the probability distributions by normal distributions in the design point situated on the failure boundary. The objective in selection of performance factors is closeness to a target safety level expressed in terms of the target safety index. A computer program was developed to be used in calibration. The procedure is illustrated by examples.

Cluster analysis as a tool in the classification of structures for safety differentiation

1988 ◽  
Vol 15 (4) ◽  
pp. 601-608
Author(s):  
Carlos Ferregut
Keyword(s):  
Cluster Analysis ◽  
Highway Bridges ◽  
Structural Type ◽  
Limit States ◽  
Safety Level ◽  
Code Calibration ◽  
New Concepts ◽  
Safety Parameters ◽  
The Difference ◽  
Selection Of

Different structures and different structural members should reasonably be assigned different levels of reliability to obtain optimum structural performance. This differential assignment of reliabilities or safety parameters is called "safety level differentiation." Up to the present, no simple practical rationale is available for the selection of safety levels. This paper presents a methodology for the selection of safety levels. Cluster analysis is suggested as a tool in the calibration of limit states design codes. The technique may be used to develop importance factors for the design loadings and resistances, reflecting the difference in consequences of failure. The cluster analysis serves to classify a structure according to various attributes that together reflect its social and economic importance. For code specification purposes, it is fundamental to identify which structures in a set are similar, because it facilitates the specification of a single set of code parameters for each structural type, and permits a more rational selection of importance factors. The acceptable number of structural types and the effect of weighing the attributes are also discussed. Some of the new concepts are illustrated using a sample of highway bridges in southwestern Ontario. Key words: safety differentiation, reliability, cluster analysis, code calibration, bridge classification.

RELIABILITY OF CORRODED STIFFENED PLATE SUBJECTED TO UNIAXIAL COMPRESSIVE LOADING

2021 ◽  
Vol 162 (A4) ◽  
Author(s):  
K Woloszyk ◽  
Y Garbatov
Keyword(s):  
Mechanical Properties ◽  
Reliability Index ◽  
Structural Reliability ◽  
Limit State ◽  
Plate Thickness ◽  
Thickness Reduction ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Initial Imperfections ◽  
Subsequent Decrease

The work is focused on the reliability of corroded stiffened plates subjected to compressive uniaxial load based on the progressive collapse approach as stipulated by the Common Structural Rules for Bulk Carriers and Oil Tankers, employing the limit state design. Two different cases have been investigated. In the first model, the corrosion degradation led to uniform thickness loss, whereas the mechanical properties were unchanged, as given in the Rules. In the second model, the plate thickness degradation was followed by mechanical properties reduction. The uncertainties related to the mechanical properties, thicknesses, and initial imperfections of the corroded stiffened plate were taken into account. Several initial design solutions of stiffened plates, as well as different severity levels of corrosion degradation were investigated. The results show that structural reliability significantly decreases with corrosion development, especially when in addition to the initial imperfections and corrosion plate thickness reduction, corroded plate surface roughness and the changes in the mechanical properties were considered. The uncertainties, their origins and confidence levels are discussed. It was found that non-linear time-dependent corrosion degradation accounting not only for the thickness reduction due to corrosion wastage but also the subsequent decrease of mechanical properties lead to a significant reduction in the reliability index. Additionally, it was defined that the reliability estimate is very sensitive to the uncertainties related to the initial thickness and the spread of corrosion degradation as a function of the time. Incorporating the probability of corrosion detection into the original reliability model introduces additional information about the validity of structural degradation that may lead to a higher beta reliability index estimate compared to the original model.

Determination of Basic Wind Velocity for Wind Load-Governed Limit State

2019 ◽  
Author(s):  
Ji Hyeon Kim ◽  
Hae-Sung Lee
Keyword(s):  
Wind Velocity ◽  
Reliability Index ◽  
General Procedure ◽  
Limit State ◽  
Wind Load ◽  
Wind Pressure ◽  
Load Factor ◽  
Load Effect ◽  
Design Life ◽  
Target Reliability Index

<p>This paper proposes a general procedure for evaluating a nominal value of wind velocity for a wind load- governed limit state to secure a target reliability index during the design life of a structure. The nominal value of wind velocity, referred to as a basic wind velocity, and wind load factor should be determined so that the factored wind load effect secures a target reliability index for a wind load-governed limit state. In this study, the analytical form of the return period of the basic wind velocity is expressed as a function of the target reliability index, wind load factor, and statistical parameters of wind pressure, which are derived as linear functions of the coefficient of wind velocity. The proposed approach is applied to the Korean Highway Bridge Design Code-Cable supported Bridge, which specifies the design life of a structure as 100- and 200-year.</p>

Toward Limit State Design of Ships and Offshore Structures Under Impact Pressure Actions: A State-of-the-Art Review

2006 ◽  
Vol 43 (03) ◽  
pp. 135-145
Author(s):  
Jeom Kee Paik
Keyword(s):  
Limit State ◽  
Structural Response ◽  
Time History ◽  
Rate Sensitivity ◽  
Offshore Structures ◽  
Impact Pressure ◽  
Green Water ◽  
Limit State Design ◽  
Structural Capacity ◽  
Pressure Time

In design of ships and ship-shaped offshore units, issues related to impact pressure actions arising from sloshing, slamming, green water, or explosion are of particular concern. The structural response under impact pressure actions is quite different from that under static or quasistatic actions. It has been recognized that the limit state approach is a more rational basis for structural design and safety assessment where both "demand" (loads) and "capacity" (strength) must be accurately defined. For impact pressure action cases, the demand is associated with hydrodynamics areas, taking into account the characteristics of impact pressure-time history, and the structural capacity is associated with structural mechanics areas, considering geometric and material nonlinearities together with strain rate sensitivity. This paper reviews recent advances and trends toward future limit state design of ships and offshore structures under impact pressure actions.

System Reliable Probability for Multi-AUV Cooperative Systems under the Influence of Current

2019 ◽  
Vol 72 (06) ◽  
pp. 1649-1659
Author(s):  
Qingwei Liang ◽  
Tianyuan Sun ◽  
Junlin Ou
Keyword(s):  
Marine Environment ◽  
Reliability Index ◽  
Autonomous Underwater Vehicle ◽  
Influencing Factor ◽  
Practical Method ◽  
Underwater Vehicle ◽  
Cooperative Systems ◽  
Cooperative System ◽  
Structure Selection ◽  
Selection Of

Real multi-Autonomous Underwater Vehicle (AUV) cooperative systems operate in complicated marine environments. The interaction between a multi-AUV cooperative system and its marine environment will affect the reliability of the system. Current is an important influencing factor of multi-AUV cooperative systems. A reliability index of multi-AUV cooperative systems known as System Reliable Probability (SRP) is proposed in this study. A method to calculate SRP is introduced, and the influence of current on SRP is discussed in detail. Current is considered an attack source, and the degree of its influence on SRP is calculated. As an example, the performance of this method is shown on two multi-AUV cooperative systems. Results show that the influence of the same current environment on different structures of the multi-AUV cooperative systems differs. This result provides a reference for the structure selection of multi-AUV systems. This study provides a practical method to estimate the reliability of multi-AUV cooperative systems.

Reliability Analysis of Fatigue Crack Growth with JC Method Based on Scientific Materials

2011 ◽  
Vol 63-64 ◽  
pp. 882-885 ◽  
Author(s):  
Xiao Li Zou
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Normal Distribution ◽  
Crack Growth ◽  
Reliability Index ◽  
Limit State ◽  
State Equation ◽  
Fatigue Reliability ◽  
Crack Propagation Process ◽  
Log Normal

Since the fatigue crack propagation process from initial size till final fracture is affected by lots of random factors, it is difficult to evaluate the fatigue reliability. Based on reliability theory, the first order second moment method ( JC method) is adopted to analyze and compute the fatigue reliability. To account for the uncertainties of material resistance, the parameters in the deterministic fatigue crack growth rate equation and material fracture toughness are taken as random variables with Normal distribution or Log-Normal distribution. Consequently, the limit state equation of fatigue crack growth is derived. The fatigue reliability index at any moment is calculated iteratively through JC method. As a computation example, the curve of fatigue crack growth reliability index with time is presented.

Research on Design Reference Period and Structural Design Method

2011 ◽  
Vol 368-373 ◽  
pp. 2364-2368
Author(s):  
Jia Nian He ◽  
Zhan Wang
Keyword(s):  
Structural Design ◽  
Reliability Index ◽  
Design Method ◽  
Structure Design ◽  
Reference Period ◽  
Building Structure ◽  
Safety Factors ◽  
Importance Factor ◽  
Partial Safety Factors

In structure design, for expressions with partial safety factors, partial safety factors and nominal value of loads are calculated based on the presupposition that the design reference period is 50 years. When the design reference period is not 50 years, it would cause unclear reliability of building structure by using expressions with partial safety factors following correlative codes yet. It may lead to hidden dangers in that way. In order to derive expressions with partial safety factors suitable for any design reference period, two useful methods are shown in this paper, modification of partial safety factors and modification of importance factor of structures. From results of analysis, we get the conclusions that it can assure the reliability index of the expression using the method of modification of partial safety factors, and the method of modification of importance factor of structures is very simple, but cannot assure the reliability index of the expression.

French Procedure for Ageing Management Program of Safety Components

2003 ◽  
Author(s):  
Claude Faidy
Keyword(s):  
Degradation Mechanism ◽  
Management Program ◽  
Mechanism Analysis ◽  
Periodic Review ◽  
Industrial Facility ◽  
Major Step ◽  
Safety Level ◽  
The Status ◽  
Ageing Management ◽  
Selection Of

Managing ageing and remaining lifetime of an industrial facility is a concern that must be taken in account by utility as soon as possible in daily activities. The corresponding actions engaged in France are based on 3 major step that are described in the paper: • routine maintenance, • exceptional maintenance, • systematic and periodic review of safety important components and structures sensitive to ageing to assure the effectiveness of the maintenance actions and maintain a high safety level of the plant with a good competitiveness. Following different on-going programs on ageing management of different components, EDF developed its own approach, based on IAEA guidelines, in order to systematically review all the ageing management programs implemented on its 3-loop plants. The methodology is done in 3 steps: • selection of components and justification, • degradation mechanism analysis, • synthesis and consequences on maintenance programs. After a presentation of each step of the procedure a quick overview of the status of application in France is done. Comparison of the methodology with similar methodology used in different other countries is done to close the paper.

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