Vibrational Monitoring of a Concrete Beam for Bridge Damage Detection: Data Fusion Between Contact and Non-Contact Techniques

Non-destructive techniques are fundamental to evaluate the structural health of structures and infrastructures; they include both inspection and monitoring techniques, with or without contact. This paper presents the results of laboratory mechanical and vibrational tests carried out on Engineered Cementitious Composites (ECCs) in the framework of the MULTICLIMACT (MULTI-faceted CLIMate adaptation ACTions to improve resilience, preparedness and responsiveness of the built environment against multiple hazards at multiple scales) project (GA n. 101123538). A release test at different load levels was performed to analyse the behaviour of a beam in free vibration oscillations. The formation of cracks causes the decrease of material stiffness which can be highlighted by vibrational monitoring of the beam. Non-contact techniques can also be exploited for example vision-based acquisition systems: processing the data with the Digital Image Correlation (DIC) technique enables the full-field extraction of the strain field, providing information in some points of the structure where contact sensors are not located. Hence, this can also be considered a soft sensing technique. However, vision-based techniques are often limited in resolution, which depends upon the speckle applied on the specimen for DIC, thus correlation with contact techniques is needed to achieve greater robustness and accuracy.