The Applied Research Based On Wavelet Analysis In Dynamic Strain Healthy Indicator Of Bridges

Recently, not only the monitoring systems of long-span bridges are valued, but also medium and small-span bridges receive attention. In healthy monitoring system of bridges, signal processing and obtaining healthy index are the most important aspects. The wavelet analysis has been very effective in signal processing and obtaining the bridge index, it has been widely applied in practical engineering. This article puts forward the bridge health index based on dynamic strain signals and uses wavelet analysis method to analyze and process these signals. The main efforts are devoted to the following aspects:(1) This article introduces thoroughly the theory of wavelet analysis and its advantages. It focuses on wavelet transform, multi-scale analysis and denoising through wavelet. The real-time dynamic strain signals of bridge are analyzed by using the property of multi-scale analysis. It proves that it is easier to find the peak and mutative points through the multi-scale analysis.(2) This article introduces the structural health monitoring system for medium and small-span simple beam bridges. The system was builton two bridges in HaiYan, and was experienced the field driving test.After collecting the dynamic strain signals and making a preliminary analysis on those signals, this system was proved that it can run successfully. The result from decomposing and denoising the real-time dynamic strain signals by using the property of multi-scale analysis proves that this analysis method is appropriate for identification and monitoring of traffic load.(3) This article introduces the analysis method about the bridge health index based on dynamic strain signals, and the application of multi-scale analysis on the analysis method of bridge health index. This article bases on the numerical analysis software to program which is used for obtaining health index. It compares the healthy index of before denoising and after denoising and analyze the results to explain the relationship between the bridge health index and the bridge health.Besides, it proves that the result base on the denoising signals can reflect the relationship.