Subspace Rotation Method And Neural Network-based Research And Application Of Structural Damage Identification

Usually there are different-degree damage phenomena in the structure after long time or natural disaster, because of the initial defectiveness of structural material and combined action of loading and environment. After investigation, lots of building structures aren't working normally in our country recently. Especially the damage of reinforced concrete structures under hostile environment is more severe. Some buildings have congenital defectiveness about structure safety as lacking earthquake resistant design. These potential dangers will cause more severe damage if they aren't raveled out without lost of time. It's very urgently to detect these buildings' quality and safety and modify or reinforce buildings' properly. Traditional methods of reliability identification of safety depend on specialists' experience, so anthropogenic influence is very important. Recently there are many damage identification methods in order to testilng reliability identification of safety more scientific. Now damage identification method based on structure vibration is one of the hotspots. The method was used for trouble diagnosis in aerospace field and mechanical engineering originally, which was focused by civil engineering and introduced to damage identification of civil engineering as a supplement of traditional methods.The method introduced in this thesis belongs to the damage identification method based on structure vibration. Subspace Rotation referred by Zimmerman and Kaouk was used for truss originally, which is used for successive beam in this dissertation firstly, this method is sued for testing damage of mathematical model, which proves the method is useful. Secondly, the method is used for testing damage of practical bridge. It is difficult to get rotation free degree for successive beam, so information measured is incompleteness. Guyan static condensation made damage identification' to be possible. There are few uses in practice by using this method as the complexity of structural damage and effects of all kinds of factors. So in the thesis the main aim is the usage of Subspace Rotation in damage identification and structural safety identification in practiceNeural network is an advanced technology, which was used for aerospace field and mechanical engineering originally, which is used in earthquake damage testing of single story industry workshops for promoting objectivity and universal of safety testing in the thesis. Practice testifies that this method is feasible.