Study On Dynamic Damage Identification Method For Bridges Based On Frequency Response Function Signature Assuerance Cretrion

The advantages and limitations of traditional model updating damage identification method with modal parameters as input are elaborated. The characteristics of frequency response fuction (FRF) in practical tests are discussed. A bridge damage detection method based on FRF signature assuerance cretrion (SAC) is proposed. The calculation criteria and feasibility of the proposed method is discussed by numerical analysis, and then the optimized measurement point layout plans are erected. The reliability and feasibility of the proposed method are validated by laboratory model beam tests and in-situ bridge tests. The main work of the thesis is as follows:(1) A dynamic damage identification method is proposed for bridges based on frequency response function signature assuerance cretrion. Based on the model updating method, a new objective function is introduced, i.e. frequency response function signature assuerance cretrion. The basic theory and calculation process of this method is expounded.(2) It is vital to select the frequency domain of frequency response function signature assuerance cretrion. This frequency response range is selected as the straight section between first peak and the second one of the frequency response function.(3) By analyzing the numerical model, the feasibility of this method and the frequency selection correctness are verified.(4) Based on this method, the measurement point layout optimization scheme is studied.(5) With the optimization of measurement point layout, the correctness of this method is validated by the vibration experiment of model beams.(6) Furthermore, the proposed damage identification method is proved by in-situ vibration experiments of reinforced concrete box girders.