Identifying the Prestress Force in Prestressed Concrete Bridges Using Ultrasonic Technology

In this research, ultrasonic tests were performed on a prestressed concrete box-girder model to identify the prestressed force according to the acoustoelastic theory. During the tests, the ultrasonic wave was generated using piezoelectric transducers and emitted to the prestressed concrete bridge model. The concrete bridge model was subjected to three different levels of prestress force (PF), which were limited to about 30%, 50% and 80% of the ultimate tensile strength. The experimental results showed the increase in prestress force level leads to an increase in the relative change in the wave velocity and the amplitude energy of the ultrasonic wave which proved the acoustoelastic effect theory. This study contributes to the knowledge of the acoustoelastic behavior of the prestressed concrete and presents the capability of the ultrasonic system in evaluating the stress state in the prestressed concrete bridge.