Study Of Bridge Damage Diagnosis Based On Modal Analysis Theory

With the rapidly development of our traffic projects, a great deal of long span bridges have constantly rushed. Bridge have been damaged to some extent for poor nature conditions, overload or some other reasons during it's service time. In order to insure safety and security of the people's health and wealth ,It is important for us to provide scientific and credible gist to bridges' maintenance and evaluation by diagnosing bridge structural damaged position and extent and mastering the health status of bridge in commonly using state in time. It is also the focus of current bridge project.This paper mainly narrate investigative status quo and evolutive direction, then present the background and content of this project.Damage diagnosis based on curvature modval theory is an ideal damage identification. Curvature mode is a mode parameter that can perfectly reflect local characteristics variety of structure. It can be obtained directly by difference of series displacment modes of structure. Theoretical analysis indicate that certain crack or damage in structure will result in reduction of stiffness in this part, which in turn arose saltation of curvature mode curve. This offer theoretical foundation to bridgedamage diagnosis based on curvature mode theory.This essay do some study as follows based on previous researcher1. Analyzing simple supporting and continuous girder finite element model damage sensitivity to curvature mode and curvature mode difference.2. A real bridge finite element mode referred to a freeway bridge data is build in this paper. Imitate various damages of bearing, middle of span in detail. Then, analyze change rule of curvature mode , curvature mode difference and present step , crucial problem of bridge diagnosis based on then, which can provide reference to real bridge damage diagnosis.3. Bring forward bridge damage identification theory using moving load according to curvature mode, then validate it by numerical value Imitation.