Crack detection of beam-like structures under environmental ground motion excitation

In order to research into the fault detection method of bridges, a mathematical model of a simply supported beam with a cracking at mid-span is input with a whitenoise ground motion excitation. The cracking is simulated with gap element, which are able to transfer only longitudinal pressure. Response signals of vertical and longitudinal axial force are analyzed for fault detection purpose, the result have shown that the frequency spectrum of the vertical vibration signal is not sensitive to the cracking fault, while obvious side-frequencies can be examined in the frequency spectrum of longitudinal axial force signals. This indicates that the longitudinal axial force signal can be informative in structural damage detection in beam-like bridge structures, this paper can also provide reference value for bridge health monitoring research.