Allowing for a rocking datum in the analysis of drive-by bridge inspections

'Drive-By' damage detection is the concept of using sensors on a passing vehicle to detect damage in a bridge. At highway speeds, the vehicle spends a short amount of time on the bridge: it may not even go through a full cycle of vibration, resulting in only a partial signal of the bridge motion being detected. Given that the spectral resolution of standard signal processing techniques depends on the length of data in the signal, they cannot be used to identify the bridge frequency accurately. In addition, the nonlinear and non-stationary nature of the vehicle-bridge interaction system poses challenges. The aim of this study is to model a 'drive-by' bridge inspection approach using a beam in free vibration. An optimisation approach is proposed in numerical simulations as an alternative to standard signal processing techniques to overcome the challenges of short signals and the nonlinear nature of the drive-by system.