The Reliability Evaluation Method Of Existing Structures Considering The Influence Of Confidence Level In Inference

Reliability assessment of existing structures is an important part of testing current performance and predicting future life.The reliability evaluation of the existing structure should be based on the inferred results of each index.It is impossible to inferred the existing structure as if the proposed structure could provide more test samples,so there are strong uncertainties in the reliability inference process of the existing structure under the condition of small samples.The uncertain environment may lead to a large error in the evaluation result and even lead to a wrong result.In order to solve this problem,the confidence level parameter can be introduced.The value of the confidence level not only reflects the degree of uncertainty,but also can objectively evaluate the accuracy of the evaluation results and analyze the influence of the confidence level on the evaluation results.Therefore,based on the reliability of existing structures under the influence of the confidence level assessment method,can reduce in the assessment of existing structures due to the sample quantity is too less and impact of uncertainty to a certain extent,make up for the deficiency of the reliability evaluation results,under the condition of considering the confidence level is not at home and abroad to study the problem of structure reliability assessment.The purpose of this paper is to established an existing structural reliability analysis method considering the influence of confidence level and to conduct quantitative analysis on its influence.The main contents are as follows :(1)Expounding the characteristics of the existing structure and summarizing the uncertainty existing in the existing structure and summarizing the mathematical solution methods of the uncertainty problem and analyzing the advantages and disadvantages.(2)The introduction of the confidence level parameters is derived under the condition ofuncertainty both things small sample inference method,choice of normal distribution and lognormal distribution in combination with the confidence level respectively derived the distribution parameters,and a value as a case study of permanent function and geometry size derived its values and reference design,and considering the confidence level is derived under the condition of material strength of the inferential value of small sample.(3)The derivation of resistance is an important part of reliability assessment.An existing structure resistance inference method based on damage assessment considering the confidence level is established.Based on the analysis and calculation of practical cases,the recommended value of the confidence level of resistance inference is given according to the comparison results.According to JC method,the reliability analysis method of existing structure considering the confidence level is established,and the reliability analysis theory is further developed.(4)Established an existing structure reliability assessment method considering the influence of confidence level.The actual value of different random variables is different from the estimated value,and the confidence level of the estimated value is different.In this paper,we study the confidence level values of the reliability evaluation results of existing structures at single confidence level and multiple confidence levels.The results showed that the inferred values of the inferred indexes are different under different confidence levels.When the larger confidence level is taken,the inferred value decreases and the result tends to be conservative.When the confidence level is small,the inferred value increases and the result tends to be aggressive.In order to solve the uncertainty in reliability calculation and make the reliability evaluation result more scientific and credible,the reliability evaluation method of existing structure considering the level of confidence level is established in this paper.At the same time,it overcomes the limitation that the analysis results are far from the actual results due to too few sample data,creates more convenient conditions for reliability evaluation,and provides some Suggestions for the development of reliability theory.