Study Of Bridge Structure Damage Identification Method

The bridge structure is bound to having large and small damage during the service.Thanks to the potential damage, it caused enormous losses to the life and property ofpeople. As a result, it is very necessary for the damage detection of bridge structure.Damage detection methods of bridge structure at the present are mostly limited tomanual detection, simple instrumentation detection and static load test detection, etc,this kind of non-simple damage detection method. Due to there being many uncertainfactors and external factors, such as operating environment, these methods can notaccurately position and quantize the damage state of the bridge structure. Besides, forsome bridge structural damage detection and identification methods based on vibrationwith some high precision, they are largely confined to the theoretical analyses andsimulation tests. It can not be directly applied to the practical engineering examples.Thus, the research of bridge structural damage detection and identification method inhigh accuracy, high anti-jamming ability and high performance has become a new crazein domestic and foreign science and technology research and development.This article firstly introduces and compares several domestic and foreign maturebridge structural damage detection methods based on modal parameter identification ofvibration system. It summarizes systematically the advantages and disadvantages ofvarious detection methods. What’s more, this paper focuses on one of the damagedetection methods—the bridge structure damage recognition method based on thesensitivity and gives main researches and analyses. The concrete research contents canbe summarized as follows:(1) According to different modal parameters of different damage identification,the identification method based on sensitivity is subdivided into the three ways, namely,the damage detection method based on model frequent sensitivity, the one based onmodel displacement sensitivity and the one based on mobile quality sensitivity.(2)The theory thinking of damage detection method based on sensitivity is furtherresearched and analyzed. The theory thinking of various damage detection methodswill be applied by the formula, in order to achieve the purpose of damage identification. (3)The article sets the damage identification analysis method based onmobile-quality sensitivity as an example. The lower bearing type one-way railway trussbridge was modeled and analyzed by using finite element software SAP. With themethod of the added mass, it calculated the added mass’s model frequency of the bridgestructure in each unit of the bridge model under the different damage cases. And theadditional sensitivity matrix formula deduced by the theory identifies the damage levelof the bridge structure.(4)According to the results of the finite element model analysis, the bearing typeone-way railway bridge is established the real bridge model via the size ratio of1:20,and then the damage detecting test of the bridge model is carried out by using thedamage identification analysis method based on the sensitivity of moving mass. Thespecific test methods are conducted strictly according to the procedure of the damageidentification method so as to that the damage identification method based on thesensitivity for mobile quality is verified in project cases.(5)In the test process of the finite element simulation and the physical model test,the bridge structure is alternately carried though the static damage simulation and thestatic damage identification. The above detection results of the sensitivity damagedetection method based on moving mass analysis are analyzed, contrasted and verified.Finally, this article summarizes the problems which should be paid attention to inthe finite element modeling simulation and the test process. And in the finite elementsimulation and the test process of the physical model, it analyzes the realization methodof the damage simulation and the additional quality simulation and also it analyzes theinfluence on the stimulation effect in the realization process of the above simulationmethods. On the base of the above stimulation analysis and the physical model tests, theapplication of the damage recognition method based on the moving mass (additionalsensitivity matrix) in the finite element simulation and engineering projects is realizedin the article.