PSI - Issue 64

Ivan Markovic et al. / Procedia Structural Integrity 64 (2024) 1621–1627 Author name / Structural Integrity Procedia 00 (2019) 000–000

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6. Conclusions and further prospects The results showed, that DFOS can ensure exact crack monitoring in all loading stages of the reinforced concrete specimens, which is a good basis for future applications for monitoring of structures in the engineering practice. In both laboratory tests (bending beam and shear beam) the cracks could be clearly detected and localized, so the main objective of the study could be fulfilled. The crack pattern from the fibre optic cables agreed very well with the experiments and it was possible to observe the cracking at different load levels. The values of the strain peaks could be confirmed for the bending beams (by numerical non-linear FE-models and externally fixed fibre optic cables). If distributed fibre optic cables are used on real existing concrete structures, the influence of the temperature on the strains must be considered. The lab conditions allowed to ignore the influences of the temperature since the lab temperature are more-or-less constant. To solve the problem of the additional strains caused by the temperature, an additional fibre optic cable should be installed, which only measures the strain caused by the temperature. Acknowledgements The authors would like to thank to Mrs. Angela Lemos, Mr. Antonio Salazar Vásquez, Mr. Alessio Höttges and Prof. Dr. Carlo Rabaiotti, all from the University of Applied Sciences of Eastern Switzerland in Rapperswil, for the excellent technical support and valuable instructions during the measurements with optical fibres. References Barrias, António; Casas, Joan R.; Villalba, Sergi (2016): A Review of Distributed Optical Fiber Sensors for Civil Engineering Applications. In: Sensors (Basel, Switzerland) 16 (5). DOI: 10.3390/s16050748. ATENA Program Documentation – Parts 1-11.2020-2023. Cervenka Consulting Carlos Augusto Galindez-Jamioy; José Miguel López-Higuera (2012): Brillouin Distributed Fiber Sensors: An Overview and Applications. In: J. Sensors 2012, 204121:1-204121:17. Galkovski, Tena; Lemcherreq, Yasmin; Mata-Falcón, Jaime; Kaufmann, Walter (2021): Fundamental Studies on the Use of Distributed Fibre Optical Sensing on Concrete and Reinforcing Bars. In: Sensors 21 (22). DOI: 10.3390/s21227643. Henault, J.-M.; Quiertant, M.; Delepine-Lesoille, S.; Salin, J.; Moreau, G.; Taillade, F.; Benzarti, K. (2012): Quantitative strain measurement and crack detection in RC structures using a truly distributed fiber optic sensing system. In: Construction and Building Materials 37, S. 916–923. DOI: 10.1016/j.conbuildmat.2012.05.029. LUNA OBR 4600: LUNA-Data-Sheet-OBR-4600-V2.pdf. Online verfügbar unter https://lunainc.com/sites/default/files/assets/files/resource library/LUNA-Data-Sheet-OBR-4600-V2.pdf. Winkler, M., Monsberger C.M., Lienhart W., Vorwagner A., Kwapisz M. (2019): Assessment of crack patterns along plain concrete tunnel linings using distributed fiber optic sensing, in n Proceedings of the 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures 2019 Rodriguez, Gerardo; Casas, Joan R.; Villalba, Sergi (2019): Shear crack pattern identification in concrete elements via distributed optical fibre grid. In: Structure and Infrastructure Engineering 15 (12), S. 1630–1648. DOI: 10.1080/15732479.2019.1640256. Rodríguez, Gerardo; Casas, Joan R.; Villaba, Sergi (2015): Cracking assessment in concrete structures by distributed optical fiber. In: Smart Mater. Struct. 24 (3), S. 35005. DOI: 10.1088/0964-1726/24/3/035005. Villalba, Sergi; Casas, Joan R. (2013): Application of optical fiber distributed sensing to health monitoring of concrete structures. In: Mechanical Systems and Signal Processing 39 (1-2), S. 441–451. DOI: 10.1016/j.ymssp.2012.01.027.