Identification of structural parameters in a prestressed concrete beam under chloride-induced corrosion using embedded and smart-probe-based piezo sensors

In prestressed concrete (PSC) structures, corrosion in prestressing wire is one of the main problems affecting its service life. Therefore, structural health monitoring (SHM) is essential for performance evaluation and safety maintenance to prevent and reduce engineering accidents. In SHM, corrosion monitoring using the piezo sensor-based electro-mechanical impedance (EMI) technique has become a research hotspot. This paper presents the effectiveness of embedded and smart-probe-based piezo sensors (SPPS) for identifying structural parameters such as stiffness, mass, and damping in a prestressed concrete beam subjected to chloride-induced corrosion using electro-mechanical impedance (EMI) technique. The accelerated corrosion tests were conducted on a PSC beam in which SPPS was indirectly bonded, and an embedded piezo sensor (EPS) was attached to the prestressing wire inside the beam to monitor the variation in the EMI signature during the exposure of corrosion. Further, a physical model was developed in the form of spring, mass, and damper combinations to identify the deterioration in terms of structural parameters during exposure to corrosion. Based on the experimental results, it is found that EPS is effective in identifying the corrosion initiation phase, while SPPS is for the corrosion propagation and cracking phase. In terms of percentage loss, the identified stiffness loss from SPPS and EPS in the propagation phase of corrosion is about 61.56 % and 5 %, respectively.