Noninvasive empirical methods of damage identification of bridge structures using vibration data

Many methods of damage identification in bridge structures have focused on the use of either numerical models, modal parameters or non-destructive damage tests as a means of condition assessment. These techniques can often be very effective but can also suffer from specific pitfalls such as, numerical mod-el calibration issues for nonlinear and inelastic behaviour, modal parameter sensitivity to environmental and operational conditions and bridge usage restrictions for non-destructive testing. The present paper covers al-ternative approaches to damage identification of bridge structures using empirical parameters applied to measured vibration response data obtained from two field experiments of progressively damaged bridges sub-jected to ambient and vehicle induced excitation, respectively. Numerous non-modal vibration-based parame-ters are detailed and selected for the assessment of either the ambient or vehicle induced excitation data based on their inherent properties