Operational Modal Analysis of a Bridge Using Transmissibility Measurements

Recently a new technique for Operational Modal Analysis was proposed and validated. This technique makes use of transmissibility measurements only. In general, the poles that are identified from transmissibility measurements do not correspond with the system’s poles. However, by combining transmissibility measurements under different loading conditions, it has been shown that the model parameters still can be identified. For comparison and validation, this new method and an existing output-only technique using the power spectra will be applied to operational data of a bridge. The advantage of the recently proposed technique is that the operational forces are no longer assumed to be white noise. They can be arbitrary (colored noise, swept sine, impact ...) as long as they are persistently exciting in the frequency band of interest.