This paper introduces a new method for analyzing nonlinear and non-stationary data-Hilbert-Huang transform

and applies it to the structural damage detection.The simulation experiment is that the three layer shear type building structure is excited by two earthquakes with different intensities

and the structural damage in this process is simulated by interlayer stiffness attenuation method approximately.We use Butterworth low-pass filter to filter every-floor acceleration data gained in the experiment

then use Hilbert-Huang transform to analyze the data already filtered to get the Hilbert spectrum.Through analyzing the Hilbert spectrum

results show that with this method

the damage information can be extracted from the measured response data effectively and the health conditions about the structure can be monitored.