Application of Hilbert-Huang transform analysis to health monitoring of Nanjing Yangtze River Bridge

This paper presents an application of Hilbert-Huang transform (HHT) analysis to health monitoring for the Nanjing Yangtze River Bridge (NYRB), and a new method based on the empirical mode decomposition (EMD) to eliminate local strong disturbance from strain signals of main truss members of the NYRB. Firstly, measured vibration signals are decomposed into several intrinsic mode functions (IMFs) and a residue through EMD. Secondly, the signal amplitude and instantaneous frequency as a function of time, and frequency-time distribution of the amplitude designated as the Hilbert-Huang amplitude spectrum are obtained. Measured strain data of the NYRB with the disturbance of interphone are purified. Results of processing and analysis of measured signals of NYRB by using HHT as the train passing show the feasibility and validity of the method in this paper. It also has demonstrated that the original data can be reconstructed with only four IMFs.