Modal analysis and finite element model updating of civil engineering structures using camera-based vibration monitoring systems

Considerable effort has been invested in recent years on developing increasingly sophisticated camera-based vibration monitoring systems. However, their application in experimental and operational modal analysis leading to full dynamic characterisation of structures remains sparse. In particular, the high-end information such as modal damping and modal mass has rarely been reported. This information is necessary for the assessment of dynamic structural behaviour under various types of loading, calibration of numerical models of structures, and can serve in structural health monitoring. To address this gap in current knowledge, the research presented in this thesis provides some of the first evidence for the applicability of vibration monitoring systems based on consumer-grade camera and image processing algorithms available in open access domain in (i) experimental modal analysis, that is input-output modal identification relying on the use of instrumented hammer and electromechanical shaker based on measurements conduced in laboratory environments, (ii) operational modal analysis, that is output only modal identification based on data collected from a large-scale in situ bridge (iii) finite element model updating. In all cases, the performance of the examined camera-based vibration monitoring systems is benchmarked against the performance of conventional systems relying on wired accelerometers and/or laser Doppler velocimetry, and/or commercial camera-based vibration monitoring systems. Overall, it is concluded that the examined systems can provide high quality data enabling modal analysis and finite element model updating, although their successful application requires consideration of a number of issues related to the sensitivity, nature of the excitation force, and signal and image processing. Based on the findings derived from the conducted work, recommendations for the use of camera-based vibration monitoring systems are given, aiding in their implementation in engineering practice.