Damage Detection Of Girder Bridges Based On Curvature Modal Analysis

Structure damage detection has become a focus in the Civil Engineering. There are a lack of uniform theories and methods available, due to the not-so-mature developing period. This thesis contributes to a study on damage detection of girder bridge through curvature mode methods belonging to the group of frequency-domain methods.This thesis is organized around four chapters giving a detailed account of the research as following, with an emphasis on the rationale behind:1) In addition to the significance, content and methods about the damage identification applied for bridge structures, some information of research status and achievements is illustrated. The scope and major work of this thesis are also described.2) The theoretical basis is developed for the curvature modal analysis and the curvature mode properties such as orthogonality. Moreover, five damage detection criteria of curvature mode eigenvalue are adopted, and the function equations of curvature frequency response are derived.3) In light of the numerical models of a simply-supported beam bridge and a continuous girder bridge, curvature mode eigenvalue calculation procedure based on MATLAB has been given, according to the simulation of the structural dynamic response through ANSYS and noise factors which has also been taken into consideration. Thus, the identification results prove the feasibility, availability and applicability of damage detection criteria for curvature mode eigenvalue used for damage detection of girder bridge.4) Results of the research through this thesis are as follows: five damage detection criteria based on curvature mode can be applied to the damage identification of both simply supported beam bridge and continuous girder bridge effectively, and also gains their own chief characteristics, applying scopes on the condition that noise level is relatively low and damage relatively develops.5) The conclusion part is about a summation of the content and results derived from the research mentioned in the preceding chapters, as well as the problems still existing in the damage identification and health monitoring of bridge structure.