AN INTEGRATED APPROACH FOR STRUCTURAL HEALTH MONITORING OF CONCRETE STRUCTURES BASED ON ELECTROMECHANICAL ADMITTANCE AND GUIDED WAVES

Summary. An integrated monitoring approach for near and far-field damage detection in concrete structures based on simultaneous use of electromechanical admittance and guided wave propagation is presented in this work. The proposed sensing system uses arrays of PZT patches bonded on the surfaces of concrete structures which are serving as multi-mode sensors/actuators. This innovative technique takes advantage of two PZT basic capabilities: a) to serve as near-field damage detection sensors using the high-frequency electromechanical (E/M) admittance monitoring technique and b) to serve as far-field damage detection sensors using guided wave propagation monitoring technique. In the guided wave propagation, one PZT patch acts as actuator and launches an elastic wave through the structure, which then can be measured by another PZT patch which in the same time serves as admittance sensor. The integration approach of both two methodologies is then straightforward because the same piezoelectric patch can be used for both methods. This integration approach is experimentally validated in this work by inspecting the sensing capabilities of custom-made “multi-mode” sensing system for damage detection of concrete structures.