Monitoring Cable Tension Force Using Optical Fiber Sensor-Embedded Strand for a Cable-Stayed Bridge

Young-Soo Park; Sung-Tae Kim; Sung-Yong Park; Jae Seok Kim; Moonsuk Park; Young-Hwan Park

doi:10.22725/JSRP.2024.2.1.19

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Research Article

Monitoring Cable Tension Force Using Optical Fiber Sensor-Embedded Strand for a Cable-Stayed Bridge 광섬유가 매립된 강연선을 이용한 사장교 케이블 모니터링

30 June 2024. pp. 19-29

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Abstract

Cables in cable-stayed bridges are critical components for load transfer, and monitoring their condition is essential for evaluating the structural safety of the bridge. The condition of the cables is generally assessed by monitoring tension and damping ratio using the vibration method with accelerometers. This method converts measured data into the frequency domain, estimating tension and damping ratio from the detected peak information. Peak information can vary due to external influences (such as vibrations and wind) and the propoerties of the cable. Inaccurate peak information affects the estimation of tension and damping ratio, making accurate cable condition assessment difficult. Additionally, the estimation of tension using the vibration method requires data acquisitionover a cetatin period of time, limiting real-time monitoring. In this study, a carbon fiber rod embedded with an FBG (Fiber Bragg Grating) sensor, one of the optical fiber sensors, was developed. This carbon fiber rod was used as a core wire to produce a new type of prestressing steel strand. The handling issues of conventional optical fiber sensors were resolved, and the temperature influence coefficient of the developed strand was determined through indoor experiments. This coefficient improved the temperature sensitivity drawback of optical fibers. The developed strand was installed on the cables of an operational cable-stayed bridge in South Korea, and its accuracy in tension estimation and field applicability were verified through comparison with existing systems.

Keywords

smart CFRP strand

cable monitoring

tension

FBG sensor

temperature compensation

사장교의 케이블은 하중을 전달하는 중요한 부재로서, 사장교의 구조적 안전성 평가를 위해서는 케이블 상태 모니터링이 필요하다. 케이블 상태는 대부분 가속도계를 이용한 진동법을 통해 장력과 감쇠비를 모니터링하여 평가한다. 진동법은 계측된 데이터를 주파수 영역으로 변환하여, 탐지된 첨두 정보를 통해 장력과 감쇠비를 추정한다. 첨두 정보는 외부 영향(진동, 바람 등), 케이블의 제원에 따라 변화된다. 부정확한 첨두 정보는 장력과 감쇠비 추정에 영향을 주어, 정확한 케이블 상태 평가에 어려움이 있다. 또한, 진동법을 통한 장력 추정은 일정 시간 이상 계측된 신호가 필요하여, 실시간 계측이 어렵다. 본 연구에서는 광섬유 센서 중 하나인 FBG센서가 매립된 탄소섬유 봉을 제작하고, 제작된 탄소섬유 봉을 강연선 심선으로 대체한 강연선을 제작하였다. 기존 광섬유 센서의 단점인 취급 문제를 개선하였으며, 실내실험을 통해 제작된 강연선의 온도영향계수를 확인하였다. 온도영향계수를 이용하여 온도 보상을 통해 정확한 장력 추정이 가능하였으며, 온도에 민감한 광섬유의 단점을 개선하였다. 개발된 강연선을 공용 중인 국내 사장교 케이블에 설치하여, 장력 추정의 정확성과 현장 적용성 등을 기존 시스템과 비교 검증하였다.

키워드

스마트 CFRP 강연선

케이블 모니터링

장력

FBG 센서

온도보상

References

Abdel-Jaber, H. and Glisic, B. (2019) Monitoring of Long-term Prestress Losses in Prestressed Concrete Structures using Fiber Optic Sensors. Structural Health Monitoring 18(1), 254-269.

10.1177/1475921717751870

Bursi, O. S., Tondini, N., Fassin, M. and Bonelli, A. (2016) Structural Monitoring for the Cyclic Behaviour of Concrete Tunnel Lining Sections using FBG Sensors. Structural Control and Health Monitoring 23(4), 749-763.

10.1002/stc.1807

Cho, H.-N., Kang, K.-K. and Cha, C.-J. (2005) Reliability-based Managing Criteria for Cable Tension Force in Cable-stayed Bridges. Journal of the Korea Institute for Structural Maintenance and Inspection 9(3), 129-138. (In Korean)

Hu, Y., Yang, Y., Tang, B., Wu, Q. and Huang, W. (2018) A monitoring and Warning System for Expressway Slopes using FBG Sensing Technology. International Journal of Distributed Sensor Networks 14(5), 1550147718776228.

10.1177/1550147718776228

Imai, M., Okubo, K., Sogabe, N., Tobe, H., Oikawa, M., Nakaue, S. and Hayakawa, M. (2019) Stress Distribution Monitoring of Ground Anchor using Optical Fiber-embedded Strand. In Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2019 (Vol. 10970, p. 109701J). International Society for Optics and Photonics.

10.1117/12.2514201

KALIS (Korea Authority of Land & Infrastructure Safety). (2022) Status of Installation of Bridge Instruments Subject to Management. (In Korean)

KICT (Korea Institute of Civil Engineering and Building Technology). (2023) Yearbook of Road Bridge and Tunnel Statistics. (In Korean)

Kim, H., Ki, S., Choi, S., Kim, J. and Park, S. (2016) The Case Study of Cable Inspection Method for Cable-Stayed Bridge. Proceedings of the Conference, 2016(11), 101. Korea Bridge and Structural Engineering Society. (In Korean)

Kim, J. M., Kim, C. M., Choi, S. Y. and Lee, B. Y. (2017) Enhanced strain measurement range of an FBG sensor embedded in seven-wire steel strands. Sensors 17(7), 1654.

10.3390/s1707165428718826PMC5539626

Kim, J. M., Kim, H. W., Park, Y. H., Yang, I. H. and Kim, Y. S. (2012) FBG sensors encapsulated into 7-wire steel strand for tension monitoring of a prestressing tendon. Advances in Structural Engineering 15(6), 907-917.

10.1260/1369-4332.15.6.907

Kim, S. T., Park, Y., Park, S. Y., Cho, K. and Cho, J. R. (2015) A Sensor-type PC Strand with an Embedded FBG Sensor for Monitoring Prestress Forces. Sensors 15(1), 1060-1070.

10.3390/s15010106025580903PMC4327064

Lan, C., Zhou, Z. and Ou, J. (2014) Monitoring of Structural Prestress Loss in RC Beams by Inner Distributed Brillouin and Fiber Bragg Grating Sensors on a Single Optical Fiber. Structural Control and Health Monitoring 21(3), 317-330.

10.1002/stc.1563

Meltz, G., Morey, W. W. and Glenn, W. H. (1989) Formation of Bragg Gratings in Optical Fibers by a Transverse Holographic Method. Optics Letters 14(15), 823-825.

10.1364/OL.14.00082319752980

Mieloszyk, M. and Ostachowicz, W. (2017) An Application of Structural Health Monitoring System Based on FBG Sensors to Offshore Wind Turbine Support Structure Model. Marine Structures 51, 65-86.

10.1016/j.marstruc.2016.10.006

Park, K. and Park, H. (2018) Error Factor Analysis of Cable Tension Estimation for Cable-Stayed Bridge Using Multiple Natural Frequencies of Simply Supported Model. Proceedings of the Conference, 2018(11), 11. Korea Bridge and Structural Engineering Society. (In Korean)

Perry, M., Yan, Z., Sun, Z., Zhang, L., Niewczas, P. and Johnston, M. (2014) High Stress Monitoring of Prestressing Tendons in Nuclear Concrete Vessels using Fibre-optic Sensors. Nuclear Engineering and Design 268, 35-40.

10.1016/j.nucengdes.2013.12.038

Peters, K. (2024) Advances in FBG Sensor Systems for SHM of Composite Aerospace Structures. In Structural Health Monitoring/ Management (SHM) in Aerospace Structures (pp. 131-146).

10.1016/B978-0-443-15476-8.00009-5

Rodrigues, C., Félix, C., Cavadas, F., Foito, D. and Pereira, A. (2010) Development of a Long-term Monitoring System based on FBG Sensors Applied to Concrete bridges. Engineering Structures 32(8), 1993-2002.

10.1016/j.engstruct.2010.02.033

Sung, H. J., Park, J. W., Park, J. H., Lee, H. S. and Jung, H. J. (2012) Temperature Compensation of Optical FBG Sensors Embedded Tendon for Long-term Monitoring of Tension Force of Ground Anchor. Journal of the Korean Geotechnical Society 28(5), 13-25.

10.7843/kgs.2012.28.5.13

Information

Publisher :Korean Institute of Bridge and Structural Engineers
Publisher(Ko) :한국교량및구조공학회
Journal Title :Journal of Structure Research and Practice
Journal Title(Ko) :한국교량및구조공학회 논문집
Volume : 2
No :1
Pages :19-29
Received Date : 2024-05-28
Revised Date : 2024-06-20
Accepted Date : 2024-06-20
DOI :https://doi.org/10.22725/JSRP.2024.2.1.19

Journal of Structure Research and Practice ISSN:3022-4241(Print) 3022-7267(Online) 한국교량및구조공학회 논문집

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