An Integrated Third-Moment method for Structural Reliability with Correlated Input Variables

2018 ◽  
Author(s):  
Chao-Huang Cai ◽  
Zhao-Hui Lu ◽  
Yan-Gang Zhao
Keyword(s):  
Moment Method ◽  
Structural Reliability ◽  
Input Variables ◽  
Third Moment

scholarly journals A Simple Third-Moment Method for Structural Reliability

2006 ◽  
Vol 5 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Yan-Gang Zhao ◽  
Zhao-Hui Lu ◽  
Tetsuro Ono
Keyword(s):  
Moment Method ◽  
Structural Reliability ◽  
Third Moment

An Efficient Response Surface Method Using Givens Transformation for Structural Reliability Analysis

2012 ◽  
Vol 532-533 ◽  
pp. 408-411
Author(s):  
Wei Tao Zhao ◽  
Yi Yang ◽  
Tian Jun Yu
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Limit State ◽  
State Function ◽  
Limit State Function ◽  
Surface Method ◽  
Mathematical Techniques ◽  
Input Variables ◽  
Improved Accuracy

The response surface method was proposed as a collection of statistical and mathematical techniques that are useful for modeling and analyzing a system which is influenced by several input variables. This method gives an explicit approximation of the implicit limit state function of the structure through a number of deterministic structural analyses. However, the position of the experimental points is very important to improve the accuracy of the evaluation of failure probability. In the paper, the experimental points are obtained by using Givens transformation in such way these experimental points nearly close to limit state function. A Numerical example is presented to demonstrate the improved accuracy and computational efficiency of the proposed method compared to the classical response surface method. As seen from the result of the example, the proposed method leads to a better approximation of the limit state function over a large region of the design space, and the number of experimental points using the proposed method is less than that of classical response surface method.

scholarly journals Research on Bridge Structure Reliability Evaluation due to Vessels Collison Based on a Statistical Moment Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tao Fu ◽  
Yang Liu ◽  
Zhixin Zhu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Moment Method ◽  
Structural Reliability ◽  
Statistical Moment ◽  
Bridge Structure ◽  
Element Analysis ◽  
Performance Function ◽  
Structural Resistance ◽  
Collision Force

Damage to bridge structures caused by vessel collision is a risk for bridges crossing water traffic routes. Therefore, safety around vessel collision of existing and planned bridges is one of the key technical problems that must be solved by engineering technicians and bridge managers. In the evaluation of the reliability of the bridge structure, the two aspects of vessel-bridge collision force and structural resistance need to be considered. As there are many influencing parameters, the performance function is difficult to express by explicit function. This paper combines the moment method theory of structural reliability with finite element analysis and proposes a statistical moment method based on finite element analysis for the calculation of vessel-bridge collision reliability, which solves the structural reliability problem with a nonlinear implicit performance function. According to the probability model based on current velocity, vessel velocity, and vessel collision tonnage, the estimate points in the standard normal space are converted into estimate points in the original state space through the Rosenblatt reverse transform. According to the estimate points in the original state space and the simplified dynamic load model of vessel-bridge collision, the sample time-history curve of random vessel-bridge collision force is generated, the dynamic response of the bridge structure and the structural resistance of the bridge are calculated by establishing a finite element model, and the failure probability and reliability index of the bridge structure is calculated according to the fourth-moment method. The statistical moment based on the finite element analysis is based on the finite element analysis and the moment method theory of structural reliability. The statistical moment of the limited performance function is calculated through a quite small amount of confirmatory finite element analysis, and the structural reliability index and failure probability are obtained. The method can be widely used in existing finite element analysis programs, greatly reducing the number of finite element analyses needed and improving the efficiency of structural reliability analysis.

Moment Method with Box–Cox Transformation for Structural Reliability

2020 ◽  
Vol 146 (8) ◽  
pp. 04020086 ◽  
Author(s):  
Chao-Huang Cai ◽  
Zhao-Hui Lu ◽  
Yan-Gang Zhao
Keyword(s):  
Moment Method ◽  
Structural Reliability ◽  
Box Cox Transformation

Probabilistic Model of Corrosion in Reinforced Concrete Structures Considering Coupling Effects of Influence Factors

2013 ◽  
Vol 671-674 ◽  
pp. 740-745
Author(s):  
Xiao Gang Zhang ◽  
Jiao Wang
Keyword(s):  
Probabilistic Model ◽  
Moment Method ◽  
Influence Factors ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Corrosion Process ◽  
Chloride Ingress ◽  
Coupling Effects ◽  
The Third ◽  
Third Moment

A probabilistic model of the chloride-induced corrosion process is provided in this paper. Based on the Third-moment method, the uncertainty of various influence factors and the coupling effects of them are concerned. Considering the corrosion process as a statistic process, the probability of corrosion initiation at certain time can be obtained. Moreover, the effect of micro-crack in chloride ingress is taken into account, too. Due to the results of stochastic analysis, the surface chloride concentration is the most important factor that affects the corrosion probability, while the thickness of concrete cover, chloride diffusion coefficient, environmental relative humidity, critical threshold chloride concentration, micro-crack rate, water-to-cement ratio and temperature are also important factors. And the Third-moment method is proved to be reasonable in the durability assessment of corrosion-induced concrete structure. The results in this paper can be used to predict the rest life of corrosion-induced concrete structures.

scholarly journals Reliability Assessment of Steel-Concrete Composite Beams considering Metal Corrosion Effects

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Trong-Ha Nguyen ◽  
Duy-Duan Nguyen
Keyword(s):  
Structural Reliability ◽  
Global Sensitivity Analysis ◽  
Metal Corrosion ◽  
Sensitivity Analyses ◽  
Cross Sectional ◽  
First Order ◽  
Industrial Structures ◽  
Input Parameters ◽  
Sobol’S Method ◽  
Input Variables

Steel-concrete composite (SCC) beams have been widely used in civil engineering and industrial structures. This kind of structure has some advantages such as fast fabrication time and optimized weight. However, designers are often concerned about the initial reliability, while over time the structural reliability will be reduced, especially due to metal corrosion. The objective of the paper is to assess the structural reliability of corroded SCC beams, in which the input parameters are considered as random variables. The SCC beam has been designed according to Eurocode-4 (EC-4), in which input parameters consist of cross-sectional dimensions of the beam, material properties, and applied loads. The effects of the random input variables on the reliability of structures are evaluated by sensitivity analyses, which are calculated by the global sensitivity analysis using Sobol’s method and Monte Carlo simulation. The developed reliability analysis algorithm in this study is verified with previous studies, highlighting the capability of the used method. Four different corrosion levels, which are pristine, 10-year, 20-year, and 50-year, are considered in the sensitivity analyses of the SCC beam. Finally, a series of first-order and total-order Sobol’s indices are obtained for measuring the sensitivity of input parameters with four corrosion levels.

An improved high-order statistical moment method for structural reliability analysis with insufficient data

2017 ◽  
Vol 232 (6) ◽  
pp. 1050-1056 ◽  
Author(s):  
Tianxiao Zhang ◽  
David He
Keyword(s):  
Reliability Analysis ◽  
Moment Method ◽  
Structural Reliability ◽  
Statistical Moment ◽  
High Order ◽  
Structural Systems ◽  
Insufficient Data ◽  
Reliability Calculation ◽  
Calculation Results ◽  
Statistical Moment Method

The fourth-order moment method for reliability analysis of structural systems can be practically applied to effectively address the problem of reliability calculation and analysis with insufficient probability data. For complicated reliability analysis problems, however, this method can lead to inaccurate and unstable reliability calculation results. In this paper, an improved high-order statistical moment method for structural reliability analysis with insufficient data is presented. The presented method is inferred using the properties of statistical moment of standard normal distribution parameter and therefore is possible to obtain more stable and accurate calculation of the reliability indexes of a structural system with insufficient probability data. Two numerical examples are provided to show the performance of the presented method. The example results have shown that the method proposed in this paper not only improves the calculation accuracy and stability, but also brings the calculation results closer to the project conditions. The developed high-moment method for reliability calculation of structural systems provides a practical and effective theoretical base and technical support for the reliability design of structural systems.

scholarly journals Improved Calculation of Load and Resistance Factors Based on Third-Moment Method

2021 ◽  
Vol 11 (19) ◽  
pp. 9107
Author(s):  
Jiao Wang ◽  
Xinying Ye ◽  
Weiji Zheng ◽  
Peng Liu
Keyword(s):  
Moment Method ◽  
Random Variables ◽  
Reliability Design ◽  
Resistance Factors ◽  
Iterative Computation ◽  
Load And Resistance Factors ◽  
Applicable Range ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Third Moment

Load and resistance factor design (LRFD) is widely used in building codes for reliability design. In the calculation of load and resistance factors, the third-moment method (3M) has been proposed to overcome the shortcomings (e.g., inevitable iterative computation, requirement of probability density functions (PDFs) of random variables) of other methods. With the existing 3M method, the iterative is simplified to one computation, and the PDFs of random variables are not required. In this paper, the computation of load and resistance factors is further simplified to no iterations. Furthermore, the accuracy of the proposed method is proved to be higher than the existing 3M methods. Additionally, with the proposed method, the limitations regarding applicable range in the existing 3M methods are avoided. With several examples, the comparison of the existing 3M method, the ASCE method, the Mori method, and the proposed method is given. The results show that the proposed method is accurate, simple, safe, and saves material.

Reduced Partial Factors for Assessment in Uk Assessment Standards

2018 ◽  
Author(s):  
C. R. Hendy ◽  
L. S. Man ◽  
R. P. Mitchell ◽  
H. Takano
Keyword(s):  
Structural Reliability ◽  
Distribution Model ◽  
Reference Period ◽  
Minimum Level ◽  
Design Standards ◽  
Reliability Level ◽  
Assessment Standards ◽  
Input Variables ◽  
Distribution Type ◽  
The Cost

Design standards are based upon a range of input variables for resistance, action and modelling. The distribution type and parameters for each determine the partial factors appropriate to achieve a defined reliability level over a specified reference period. For assessment a reduced reliability level may be accepted due to the greater cost of providing reliability through strengthening when compared to the cost of providing it at design. This would allow the use of lower partial factors, although they are still limited by the need to provide a minimum level for human safety. Adoption of this approach for assessment would have significant benefits for an ageing UK infrastructure by reducing the need to carry out costly strengthening and retrofitting schemes whilst still ensuring appropriate structural reliability levels are maintained. This paper presents a study investigating appropriate reduced partial factors to be applied through UK assessment standards, the sensitivity of these values to input distribution model assumptions, and how they could be implemented in industry.

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