ABSTRACT
Drive-by bridge health monitoring is hindered by the adverse effects of the road surface. In this paper, noisy accelerations are simulated for the unsprung mass of a quarter-car crossing a beam with a rough road profile at two different speeds. The fast Fourier transform, and the transfer function are applied to extract real and imaginary parts of the response of the contact point with the bridge, thus mitigating the impact of vehicle-related factors. The responses for the two speeds are subtracted in the spatial domain to isolate the bridge component within the resulting power spectral density, effectively removing the influence of the road profile. Damage is characterized by comparison with a database of power spectral densities derived from the contact point response of a moving constant force. The methodology exhibits great accuracy in identifying the damage caused by a localized crack of size 10% to 30% of the beam depth.
