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.

中文翻译：

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使用超声波技术识别预应力混凝土桥梁中的预应力

在这项研究中，对预应力混凝土箱梁模型进行了超声波测试，以根据声弹性理论识别预应力。在测试过程中，使用压电换能器产生超声波并发射到预应力混凝土桥梁模型。混凝土桥梁模型承受三个不同水平的预应力（PF），分别限制在极限抗拉强度的 30%、50% 和 80% 左右。实验结果表明，预应力水平的增加导致超声波波速和振幅能量的相对变化增加，这证明了声弹效应理论。