PSI - Issue 64

Mingyang Xi et al. / Procedia Structural Integrity 64 (2024) 515–522

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Mingyang Xi et al. / Structural Integrity Procedia 00 (2024) 000 – 000 Combined with the on-site monitoring data and shown in Figure 3-5, according to the tensioning construction conditions (initial force of the strands before tensioning was 0), the tensioning force of the 4 strands ranged between 186~194KN, all exceeding 95% of the locking force, meeting the design requirements. This indicates that the self sensing strands are capable of real-time monitoring and ensuring the accuracy of the tensioning force during the construction process, thereby guaranteeing the stability and safety of the bridge structure. Additionally, since the 4 beams had a longer maintenance period (over 15 days), the prestress loss within the first 24 hours of prefabrication and during the anchorage grouting stage was minimal, with an average prestress loss of 0.43 KN. This corresponds with the slow formation of the designed camber and the characteristics of the N5 bundle being a continuous bottom plate bundle, further verifying the effectiveness and reliability of self-sensing strands in monitoring bridge prestress. 4. Conclusion This study demonstrated the application of self-sensing strands in prestressed concrete beams, through an actual application case analysis of a bridge construction project in southern China. By integrating Fiber Bragg Grating (FBG) sensors into the strands, real-time dynamic health monitoring of bridges and other infrastructure was achieved. This new type of self-sensing strand not only possesses excellent mechanical properties but also accurately monitors the internal stress conditions during the maintenance period of concrete box girders. The monitoring data from the self sensing strands indicate: (1) The amount of prestress loss within the first 24 hours of box girder prefabrication and during the anchorage grouting stage is minimal, with an average prestress loss of 0.43 KN, consistent with structural characteristics. (2) During the maintenance period of the concrete box girders, the tensioning force of the four internal strands ranged between 186~194KN, all exceeding 95% of the locking force, meeting the design requirements. The monitoring data prove that prestressed self-sensing strands can effectively monitor prestress loss while ensuring structural stability and safety, significantly reducing maintenance costs. It also provides reliable support for the intelligent operation and maintenance, and long-term health monitoring of bridge structures, marking a significant advancement in the field of construction and structural engineering. This showcases the tremendous potential of smart building materials in promoting the sustainable development of infrastructure. Hou, Z., Long, P., Zhuge, P., Liu, M., 2013. Experiment on Mechanism of Bond-type Anchor for CFRP Cables. China Journal of Highway and Transport (05),95-101. doi:10.19721/j.cnki.1001-7372.2013.05.013. Li, M., Liu, F., Wu, X., Wei, W., Zhu, W., 2021. Application of Self-sensing Steel Strand with Multiple Measuring Points in Moon Bay Bridge. Science Technology and Engineering (29),12610-12615. Pin, H., Lin, Y., Jiang, Y., Chen, F., 2020. Application of Fiber Bragg Grating Sensor in Cable Force Monitoring of Cable⁃stayed Bridge. Railway Engineering (10),51-55. Pin, H., Shi, J., Xu, H., 2021. Monitoring of Fiber Grating Self-sensing Steel Strands in Post-tensioned Bonded Prestressed Structures. Science Technology and Engineering (32),13906-13913. Pin, H., Wei, J., 2021. Monitoring Long-term Prestress Loss Caused by Prestressed Concrete Girder Based on Embedded Self-sensing Steel Strand. Railway Engineering (09),12-17. Obaydullah, M., Jumaat, M. Z., Alengaram, U. J., ud Darain, K. M., Huda, M. N., & Hosen, M. A. 2016. Prestressing of NSM steel strands to enhance the structural performance of prestressed concrete beams. Construction and Building Materials, 129, 289-301. Dang, C. N., Floyd, R. W., Hale, W. M., & Martí-Vargas, J. R. 2016. Measured development lengths of 0.7 in.(17.8 mm) strands for pretensioned beams. ACI Struct. J, 113(3), 525-535. Li, F., Du, Y., Sun, X., & Zhao, W. 2018. Sensing performance assessment of twisted CFRP with embedded fiber Bragg grating sensors subjected to monotonic and fatigue loading. Sensors and Actuators A: Physical, 271, 153-161. Fan, G. X., Lin, F. T., Li, P., Han, J. G., Shang, H. S., Wang, Y., & Zheng, H. 2020. Strain Conditions Monitoring on Corroded Prestressed Steel Strands in Beams Based on Fiber Bragg Grating Sensors. Sensors, 20(8), 2288. Koch, J., Angelmahr, M., & Schade, W. 2014, June. Fiber Bragg grating sensors for steel wire monitoring in real-time. In 23rd International Conference on Optical Fibre Sensors (Vol. 9157, pp. 1438-1441). SPIE. Qin, H. Y., Shen, Q. X., Zhu, W. X., & Zhang, H. L. 2020. Range ‐ expansion technology and fatigue performance study on the self ‐ sensing steel strand with an embedded fibre Bragg grating sensor. Strain, 56(5), e12354. Hsiao, J. K. 2016. Prestress loss distributions along simply supported pretensioned concrete beams. Electronic Journal of Structural Engineering, 16, 18-25 References