Safety Diagnosis and Evaluation Technique for PSC Bridges Using Acoustic Emission Technique

This paper describes the safety diagnosis and evaluation of actual infrastructure structures such as bridges by analyzing the condition of the tendon inside the prestressed concrete (PSC) structures and the characteristics of the fracture signal using the acoustic emission technique. In this study, based on the basic data acquired in the basic test of the first stage small PSC specimen, the reference signal was identified and the standard was established, and the characteristics of the failure signal compared to the reference signal in the second stage actual I-type girder bridge were analyzed. Comparative verification was performed in the following manner. In the case of small PSC specimens, a basic experiment on the classification of the AE signal according to the presence or absence of an abnormality in the tendon inside the PSC is performed with the aim of determining the extent of damage and the presence of damage due to repeated loads by applying different artificial defects to each of the 6 PSC specimens. In the case of the closed I-type girder closed bridge, acoustic emission signals were measured in the preload test and the actual breaking load test, and characteristic analysis according to the load change was performed. During the experiment, the secondary AE signal, which is assumed to be caused by cracks in concrete, breakage of steel wires, and voids, was measured, and based on this, the standards for safety diagnosis and evaluation technique for tendon damage inside the PSC structures are established.