Research on piezoelectric monitoring method of working stress of concrete structures

The measurement of concrete working stress is important for the safety assessment of the structure. Currently, the method for measuring the working stress of concrete is mainly the stress release method. The advantage of stress release method is direct, while the parameters of the drilling or grooving are not uniform due to stress release, resulting in different measurement results. Moreover, the stress release process is susceptible to interference from external vibrations, making the measured values inaccurate. In this paper, the concrete working stress sensor is fabricated by piezoelectric sheet. The change of the signal under the stress of the sensor is studied. The relationship between the relative peak area of the signal index and the stress is established. The sensor is imbedded in the concrete to predict the internal working stress of the concrete. The experimental results show that the average relative error of the predicted stress under lower stress is higher than the average relative error under higher stress. After the average cross-sectional stress is higher than 15 MPa, the relative error of the predicted stress is around 10%. The fabricated sensor can be used to monitor the working stress of the concrete structure, and the accuracy is higher when the stress is larger than 15 MPa.