Signals Processing And Model Analysis Of Bridge Inspection

Signal processing is one of the most important aspects in bridge inspection. So it is necessary to find a good method for analysing signals. After processing, the processed signals can represent the real-time state of the bridge better. So it plays an important role in bridge maintenance and retrofit for providing an assuring scientific evidence or index.Wavelet analysis is a new mathematic method which has developed rapidly in recent years. It is regarded as a breakthrough of Fourier analysis. It has a strong ability of analyzing about time domain and frequency domain. By using wavelet transform, the monitoring signals of bridge are described in different scales . This technique is easy and don't need complicated arithmetic, and it is required that signals are decomposed by wavelet transform, then analyses the character of signals.This thesis is introduced detailedly about signals processing by using wavelet analysis and the principle of experimental modal analysis. The main efforts are devoted to the following aspects:Firstly, This thesis is introduced thoroughly the theory of wavelet analysis and its advantages. It focuses on wavelet transform, multi-resolution analysis and denoised by using wavelet. The real-time signals of bridge are decomposed and denoised by making use of the property of multi-resolution analysis, and then extracted the property of the bridge.Then, this thesis is introduced the basis of structural dynamics, the principle of experimental modal analysis, and focuses on modal parameter identification methods . It is important to understand bridge's dynamic properties in bridge engineering. Ambient vibration test has many advantages, including no need of excitation equipment, no interruption of structural service and less test time consuming. As a result, ambient vibration test is suitable for the real working conditions of civil engineering structures. Some ractical ambient vibration test methods are discussed. Peak-picking has been used to identify vibration property. It is concluded that the test method can provide favorable reference for dynamic analysis and safety evaluation of bridge.