Prestressed steel strands are critical components of prestressed structures, which determine the bearing capacity of the structures. The prestress loss of steel strands causes the bearing capacity to decline. To monitor the stress of prestressed steel strands, a stress monitoring method based on the magnetoelastic effect was proposed. The influence of the material strain was considered to improve monitoring accuracy. To do the monitoring, a coil-based sensor, using a small excitation current to generate a necessary magnetic field, was employed. The sensor converted the stress into inductance. An experimental system was set up and two batches of specimens were tested. The experimental results showed that the measured inductance was stable and repeatable. There was a nonlinear relationship between the inductance and the stress. Strands of different batches need to be calibrated separately to obtain the inductance-stress equation. Based on the calibration equation and the measured inductance, the stress of strands could be calculated. The difference between the calculated stress and the actual stress was small. Besides, to improve the accuracy and ease of the construction, the self-induction coil of the senor should be one layer and with moderate turns.
2. Bartoli, I., S. Salamone, R. Phillips, F. Lanza Di Scalea, S. Coccia, and C. S. Sikorsky, "Monitoring prestress level in seven wire prestressing tendons by inter wire ultrasonic wave propagation," Advances in Science and Technology, Vol. 56, 200-205, 2008.
3. Bymaster, J. C., C. N. Dang, R. W. Floyd, and W. M. Hale, "Prestress losses in pretensioned concrete beams cast with lightweight self-consolidating concrete," Structures, Vol. 2, 50-57, 2015.
4. Cappello, C., D. Zonta, H. A. Laasri, B. Glisic, and M. Wang, "Calibration of elasto-magnetic sensors on in-service cable-stayed bridges for stress monitoring," Sensors (Basel, Switzerland), Vol. 18, No. 2, 466, 2018.
5. Chen, L., J. Chen, and J. Wang, "Calculation of reasonable tension value for longitudinal connecting reinforcement of CRTSII slab ballastless track," Applied Sciences, Vol. 8, No. 11, 2139, 2018.
6. Duan, Y., R. Zhang, Y. Zhao, S. Or, K. Fan, and Z. Tang, "Smart Elasto-Magneto-Electric (EME) sensors for stress monitoring of steel structures in railway infrastructures," Journal of Zhejiang University — SCIENCE A, Vol. 12, No. 12, 895-901, 2011.
7. Duan, Y., R. Zhang, Y. Zhao, S. Wing Or, K. Fan, and Z. Tang, "Steel stress monitoring sensor based on elasto-magnetic effect and using magneto-electric laminated composite," Journal of Applied Physics, Vol. 111, No. 7, 07E516-07E516-3, 2012.
8. Garcia, T., W. J. Hornof, and M. F. Insana, "On the ultrasonic properties of tendon," Ultrasound in Medicine & Biology, Vol. 29, No. 12, 1787-1797, 2003.
9. Jang, J. B., K. M. Hwang, H. P. Lee, and B. H. Kim, "An assessment of the prestress force on the bonded tendon by SI and impact signal analysis techniques," Nuclear Engineering and Design, Vol. 255, 9-15, 2013.
10. Jeong, S., W. Jang, J. Nam, H. An, and D. Kim, "Development of a structural monitoring system for cable bridges by using seismic accelerometers," Applied Sciences, Vol. 10, No. 2, 716, 2020.
11. Joh, C., J. W. Lee, and I. Kwahk, "Feasibility study of stress measurement in prestressing tendons using villari effect and induced magnetic field," International Journal of Distributed Sensor Networks, Vol. 9, No. 11, 249829, 2013.
12. Kim, Y., N. Huh, Y. Kim, Y. Choi, and J. Yang, "On relevant ramberg-osgood fit to engineering nonlinear fracture mechanics analysis," Journal of Pressure Vessel Technology, Vol. 126, No. 3, 277-283, 2004.
13. Li, C., J. He, Z. Zhang, Y. Liu, H. Ke, C. Dong, and H. Li, "An improved analytical algorithm on main cable system of suspension bridge," Applied Sciences, Vol. 8, No. 8, 1358, 2018.
14. Lv, X. J., X. F. Zhao, L. Wang, H. Dong, and Y. F. Zhu, "Research on fiber Bragg grating sensing technique for cable tension monitoring of suspension bridges," Applied Mechanics and Materials, Vol. 368–370, 1391-1395, 2013.
15. Maji, A. K., "Evaluation of prestressing with a shape memory alloy," MRS Proceedings, Vol. 503, 1997.
16. Sathyan, S., U. Aydin, A. Lehikoinen, A. Belahcen, T. Vaimann, and J. Kataja, "Influence of magnetic forces and magnetostriction on the vibration behavior of an induction motor," International Journal of Applied Electromagnetics and Mechanics, Vol. 59, No. 3, 825-834, 2019.
17. Schoenekess, H. C., "Method to determine tensile stress alterations in prestressing steel strands by means of an Eddy-current technique," IEEE Sensors Journal, Vol. 7, No. 8, 1200-1205, 2007.
18. Shu, Y., W. Chen, P. Zhang, J. Wu, L. Liu, and X. Zhao, "Embedding technology of Fiber Bragg Grating strain sensor for cable tension monitor," Proc. SPIE 9044, 2013 International Conference on Optical Instruments and Technology: Optical Sensors and Applications, 90440H-90440H-11, 2013.
19. Sumitro, S., A. Jarosevic, and M. L. Wang, "Elasto-magnetic sensor utilization on steel cable stress measurement. Monitoring," The First Fib Congress, Concrete Structures in the 21th Century, 2002.
20. Wang, M. L., "Magnetoelastic permeability measurement for stress monitoring in steel tendons and cables," Proc. SPIE 3995, Nondestructive Evaluation of Highways, Utilities, and Pipelines IV, Jun. 9, 2000.
21. Tang, D., S. Huang, W. Chen, and J. Jiang, "Study of a steel strand tension sensor with difference single bypass excitation structure based on the magneto-elastic effect," Smart Mater. Struct., Vol. 17, 25019, 2008.
22. Soohoo, R., "Magnetic thin film inductors for integrated circuit applications," IEEE T. Magn., Vol. 15, 1803-1805, 1979.
23. Zagrai, A., V. Gigineishvili, W. A. Kruse, A. Murray, D. Doyle, W. Reynolds, B. Arritt, and H. Gardenier, "Acousto-elastic measurements and baseline-free assessment of bolted joints using guided waves in space structures," Proceedings of SPIE — The International Society for Optical Engineering, 765017-7650112, 2010.