Research On Calculation Method Of Damage-symptom Correlation Of Cable-stayed Bridge Considering Modeling Uncertainty

Structural damage identification methods based on the change of static and dynamic characteristics have made great progress in the past few decades.Compared with the deterministic damage identification,the damage identification method based on the probability statistical theory framework can better reflect the uncertain nature of the damage problem and has a very broad application prospect.In this paper,based on the deterministic bridge damage diagnosis theory of symptom matching,this paper puts forward the expression method of uncertain damage diagnosis reasoning,carries out damage-symptom correlation analysis under parameter uncertainty conditions,and carries out damage-symptom support And the practical calculation method of the necessary degree,the research content is as follows:(1)On the basis of probability theory,this paper proposes the reliability distribution and finite event method for approximate calculation of subjective probability.On the basis of the above theories and methods,based on the artificial intelligence uncertainty reasoning method and the deterministic damage diagnosis model based on symptom matching,the uncertainty structure damage diagnosis model based on deterministic reasoning is proposed,and the diagnosis is given.The specific calculation methods of matching degree,support degree and certainty degree in the model,and analysis examples of truss structure damage diagnosis are carried out.Combining the reliability calculation in the process of damage-symptom support and necessity calculation,a similar combination compression method is proposed to solve the combination explosion problem in reliability calculation.(2)This paper simulates the construction process of Binzhou cable-stayed bridge.The cable-stayed bridge parameterized finite element modeling is carried out,and the model is revised based on the measured cable force and measured frequency,and the benchmark finite element model for health monitoring is determined.In order to study the correlation between cable stay damage and symptoms,the above model was used to simulate the change law of internal force indicators such as vertical displacement of bridge deck,cable force of cable stay,tower top displacement,and frequency of bridge deck system after cable stay relaxed.Considering that it is impossible for all cable stays to be equipped with cable force sensors,this paper gives the symptom conditions corresponding to cable stay damage for the measuring point arrangement of one cable force sensor for every two cables at intervals,and analyzes the symptom conditions Misjudgment and missed judgment.(3)The elastic modulus of the main beam,the elastic modulus of the cable,the elastic modulus of the middle tower,and the initial cable force of the bridge tower are regarded as uncertain parameters and expressed as interval quantities.Combining the section event reliability distribution theory and the Bayes principle,the concrete calculation algorithm of the cable stay damage-symptom support and necessity is given.The classical second-order response surface method and the multivariate cross higher-order response surface method are used to build a fast response surface calculation model to improve the reliability calculation speed,and the applicability of the two methods is analyzed for the problems in this article.Based on the above method,the cable-stayed cable damage-symptom support and necessity of Binzhou cable-stayed bridge were calculated,and the damage symptom was evaluated and optimized according to the support and necessity.