PSI - Issue 64

ScienceDirect Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ Structural Integrity Procedia 00 (2023) 000-000 Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ Structural Integrity Procedia 00 (2023) 000-000 Available online at www.sciencedirect.com Procedia Structural Integrity 64 (2024) 1681–1688

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

SMAR 2024 - 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Distributed Fibre Optic Sensors (DFOS) in Measurements of Rail Strain and Displacements Łukasz Bednarski a , Tomasz Howiacki b, * , Rafał Sieńko b , Katarzyna Zuziak c SMAR 2024 - 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Distributed Fibre Optic Sensors (DFOS) in Measurements of Rail Strain and Displacements Łukasz Bednarski a , Tomasz Howiacki b, * , Rafał Sieńko b , Katarzyna Zuziak c a AGH University in Krakow, al. Mickiewicza 30, 30-059 Kraków Poland b Cracow University of Technology, Warszawska 24, 31- 155 Kraków, Poland c SHM System / Nerve- Sensors, Libertów, Jana Pawła II 82A , 30-444 Kraków , Poland Abstract Distributed fibre optic sensing (DFOS) is increasingly used in civil engineering and geotechnical applications. The key advantage over conventional point-based measurement methods, is the ability to measure the selected physical quantities continuously over the length of the structure, from a few centimetres to several hundred kilometres. The benefits of this technique are therefore particularly evident when monitoring linear structures such as roads, embankments, bridges, tunnels, pipelines or railway lines. The result of the measurement is not a single value at a selected point, but a profile of strains, temperatures, displacements or vibrations, both as a function of time and as a function of length. This allows direct detection of local events such as cracks, stress concentrations, buckling, sinkholes, leaks and others. The article describes the application of the DFOS system using composite and monolithic sensors bonded directly to the rail. The monitoring system was launched in early 2023 in central Poland. In total, more than 2,000 metres of sensors have been installed on selected sections, making it the largest system of its kind in the world. Measurements are made on a long-term basis as part of cyclical sessions (with changing external conditions), as well as on a short-term basis (dynamic) during train passes. As the same DFOS sensors can be connected to different optical interrogators (using Rayleigh, Brillouin or Raman scattering), different system outputs can be generated (e.g. strains, displacements or vibrations). The paper summarises the lessons learned during the project. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers a AGH University in Krakow, al. Mickiewicza 30, 30-059 Kraków Poland b Cracow University of Technology, Warszawska 24, 31- 155 Kraków, Poland c SHM System / Nerve- Sensors, Libertów, Jana Pawła II 82A , 30-444 Kraków , Poland Abstract Distributed fibre optic sensing (DFOS) is increasingly used in civil engineering and geotechnical applications. The key advantage over conventional point-based measurement methods, is the ability to measure the selected physical quantities continuously over the length of the structure, from a few centimetres to several hundred kilometres. The benefits of this technique are therefore particularly evident when monitoring linear structures such as roads, embankments, bridges, tunnels, pipelines or railway lines. The result of the measurement is not a single value at a selected point, but a profile of strains, temperatures, displacements or vibrations, both as a function of time and as a function of length. This allows direct detection of local events such as cracks, stress concentrations, buckling, sinkholes, leaks and others. The article describes the application of the DFOS system using composite and monolithic sensors bonded directly to the rail. The monitoring system was launched in early 2023 in central Poland. In total, more than 2,000 metres of sensors have been installed on selected sections, making it the largest system of its kind in the world. Measurements are made on a long-term basis as part of cyclical sessions (with changing external conditions), as well as on a short-term basis (dynamic) during train passes. As the same DFOS sensors can be connected to different optical interrogators (using Rayleigh, Brillouin or Raman scattering), different system outputs can be generated (e.g. strains, displacements or vibrations). The paper summarises the lessons learned during the project. Keywords: Distributed Fibre Optic Sensing; Rail, Strains; Displacements; Measurements

Keywords: Distributed Fibre Optic Sensing; Rail, Strains; Displacements; Measurements

* Corresponding author. Tel.: +48-505-870-669 E-mail address: tomasz.howiacki@pk.edu.pl

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers 10.1016/j.prostr.2024.09.173 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V . This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organisers 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V . This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organisers * Corresponding author. Tel.: +48-505-870-669 E-mail address: tomasz.howiacki@pk.edu.pl