MISURE DI ACOUSTIC EMISSION SU SIMULACRI DI TELAI IN CALCESTRUZZO PER COSTRUZIONI CIVILI

The aging of civil infrastructure represents a critical challenge for modern en- gineering, highlighting the limitations of traditional visual inspections. To ensure structural safety and optimize maintenance, a transition toward continuous, pre- dictive Structural Health Monitoring (SHM) is essential. This thesis investigates the Acoustic Emission (AE) technique as an advanced Non-Destructive Evaluation (NDE) tool to detect, localize, and quantify damage in reinforced concrete structures before macroscopic failure occurs. An extensive experimental campaign was conducted on scaled concrete frames, both bare and masonry-infilled, subjected to induced differential settlements. A multi- sensor network, featuring wideband piezoelectric accelerometers and a Laser Doppler Vibrometer (LDV), was deployed to capture the transient high-frequency elastic waves released by early-stage micro-cracking. To isolate these low-energy acoustic signatures and extract reliable metrics, a comprehensive signal processing framework, integrating time-frequency analysis, signal envelope extraction, and statistical noise rejection, was successfully developed. By converting the raw spectral data into quantitative metrics, such as the energy- based MARSE parameter, the frequency-domain Damage Index, and inter-arrival time trends (∆T ), the structural degradation was objectively tracked. The results demonstrate the AE technique’s capability to precisely localize crack initiation, map the kinetic evolution of damage, and anticipate the ultimate structural collapse.