The Research On Bridges Structure Damage Detection

In the article a new identification index based on mode parameters is used to detect bridge structures' damage, first of all the damage positions are identificated by the method named by flexibility curvature rate method based on structure flexibility matrix. Whereafter, damage degree is calculated out by the method named bidirectional variable step adaptive genetic-algorithms, the article is made up of four chapters. The main contents and contributions of the research are summarized her.1) It claborates the significance,contents and technique of the damage identification in the field of bridge construres. Some research status quo and acquired achievements in the field home and overseas are introduced.2) In the article, a new method named by flexibility curvature rate method based on structure flexibility matrix is presented. Some correlative foemulas are deducted. The methold is used to identificate the damage positions of simple- supporting beam, continuum beam and cantilever beam by numerical simulations .3) The genetic-algorithms theory is introduced systemically. The adaptive genetic-algorithms is improved and a methold named bidirectional variable step adaptive genetic-algorithms is brought forward.4) An damage identification program based on bidirectional variable step adaptive genetic-algorithms is programmed with Matlab computer larguage and is used to identificate a simple- supporting beam's damage degree by numerical simulations. A perfect result is acquired.5) Based on the project example of arch, the research achievements and damage identification program are used to identify arch's initial damages. An result accord with the one from static load experimentation is gotten.6) the numerical simulation results and locale test result indicate that the theory and method offered in the article are reasonable and feasible to be used to identificate bridges structures' damages.