Journal of the Computational Structural Engineering Institute of Korea (한국전산구조공학회논문집)

Computational Structural Engineering Institute of Korea (한국전산구조공학회)
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Long Term Monitoring of Prestressing Tension Force in Post-Tension UHPC Bridge using Fiber Optical FBG Sensor

FBG 광섬유센서가 내장된 7연 강연선을 이용한 포스트텐션 UHPC 교량의 긴장력 장기모니터링

  • Kim, Hyun-Woo (Long Span Bridge Management Center, Korea Infrastructure Safety and Technology Corporation) ;
  • Kim, Jae-Min (Department of Marine and Civil Engineering, Chonnam National Univ.) ;
  • Choi, Song-Yi (Department of Civil and Environmental Engineering(Graduate School), Chonnam National Univ.) ;
  • Park, Sung-Yong (Division of Structural Engineering Research, Korea Institute of Construction and Building Technology) ;
  • Lee, Hwan-Woo (Department of Civil Engineering, Pukyong National Univ.)
  • 김현우 (한국시설안전공단 특수교유지관리센터) ;
  • 김재민 (전남대학교 해양토목공학과) ;
  • 최송이 (전남대학교 건설환경공학과) ;
  • 박성용 (한국건설기술연구원 구조융합연구소) ;
  • 이환우 (부경대학교 토목공학과)
  • Received : 2015.10.17
  • Accepted : 2015.11.24
  • Published : 2015.12.29
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Abstract

This paper presents results of one-year monitoring on prestressing force of a 7-wire steel post-tensioning strand which is installed in a UHPC(ultra high performance concrete) bridge with 11.0 m long, 5.0 m wide, and 0.6 m high by using a FBG-encapsulated 7-wire steel strand. The initial prestressing forces and the prestress changes during a vehicle load test were measured using the FBG-encapsulated strand. The results show that the FBG-encapsulated 7-wire strand is very effective for monitoring the prestress forces even the change in the tension force is very small. Additionally, it was indicated that selection of the thermal expansion coefficient which is used for the temperature correction shall be carefully carried out.

이 연구에서는 FBG센서가 내장된 강연선을 포스트텐션 UHPC 교량(길이 11.0m, 폭 5.0m, 높이 0.6m)에 적용하고 약 1년간의 긴장력 장기모니터링 결과를 정리하였다. 그리고 초기 도입 긴장력과 차량재하시험을 통하여 콘크리트 내부 강연선의 긴장력 변화를 계측하고 계측결과에 대한 분석을 수행하였다. 연구결과, 이 연구에서 제안하는 콘크리트 내부 긴장력 측정방법이 공영 중인 교량에서 외력으로 인한 콘크리트 내부의 작은 프리스트레스 변화를 효과적으로 측정할 수 있음을 알 수 있었다. 아울러 장기 계측결과를 이용하여 응력변화에 의한 유효변형률을 정확하게 얻기 위해서는 온도보정에 사용되는 열팽창계수의 선택이 매우 중요함을 알 수 있었다.

Keywords

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