Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Creep Behavior of Pultruded Ribbed GFRP Rebar and GFRP Reinforced Concrete Member

인발성형된 이형 GFRP 보강근과 GFRP 보강 콘크리트 부재의 크리프 거동

  • You, Young-Jun (Structural Engineering Research Division, Korea Institute of Construction Technology) ;
  • Park, Young-Hwan (Structural Engineering Research Division, Korea Institute of Construction Technology) ;
  • Kim, Hyung-Yeol (Structural Engineering Research Division, Korea Institute of Construction Technology) ;
  • Choi, Jin-Won (School of Civil and Environmental Engineering, Yonsei University) ;
  • Kim, Jang-Ho Jay (School of Civil and Environmental Engineering, Yonsei University)
  • 유영준 (한국건설기술연구원 인프라구조연구실) ;
  • 박영환 (한국건설기술연구원 인프라구조연구실) ;
  • 김형열 (한국건설기술연구원 인프라구조연구실) ;
  • 최진원 (연세대학교 사회환경시스템공학부) ;
  • 김장호 (연세대학교 사회환경시스템공학부)
  • Received : 2012.09.26
  • Accepted : 2013.02.21
  • Published : 2013.04.30
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Abstract

Fiber reinforced polymer (FRP) has been gathering interest from designers and engineers for its possible usage as a replacement reinforcement of a steel reinforcing bar due to its advantageous characteristics such as high tensile strength, non-corrosive material, etc. Since it is manufactured with various contents ratios, fiber types, and shapes without any general specification, test results for concrete members reinforced with these FRP reinforcing bars could not be systematically used. Moreover, since investigations for FRP reinforced members have mainly focused on short-term behavior, the purpose of this study is to evaluate long-term behaviors of glass FRP (GFRP) reinforcing bar and concrete beams reinforced with GFRP. In this paper, test results of tensile and bond performance of GFRP reinforcing bar and creep behavior are presented. In the creep tests, results showed that 100 years of service time can be secured when sustained load level is below 55% of tensile strength of GFRP reinforcing bar. A modification factor of 0.73 used to calculate long-term deflection of GFRP reinforced beams was acquired from the creep tests for GFRP reinforced concrete beams. It is expected that these test results would give more useful information for design of FRP reinforced members.

섬유복합체(FRP)는 비부식성 재료라는 특징으로 인해 이상적인 철근 대체재로 주목 받고 있다. 그러나 현재 FRP 보강근은 철근과 달리 일반적으로 수용되는 고정된 형태가 존재하지 않고 다양한 재료와 성분비, 형태 등으로 제작되기 때문에 이에 대한 성능평가 데이터에 근거한 FRP 보강 콘크리트 부재의 거동특성 구명은 상당부분 제한될 수 있다. 더군다나 FRP 보강 콘크리트 부재의 휨거동에 대한 평가는 주로 단기 거동 측면에 집중되어 이루어져 왔다. 이 연구는 GFRP 보강근 및 이를 사용하여 보강된 콘크리트 부재의 장기거동을 평가하기 위한 것으로, 먼저 철근 대체용으로 개발된 GFRP 보강근에 대한 성능평가 결과를 제시하였고, 이의 크리프 거동 특성에 대한 3년간의 계측 결과를 제시하였다. 실험 결과 인장강도의 약 55% 이하의 하중이 지속적으로 재하되는 경우에는 100년 이상의 내구연한을 확보할 수 있는 것으로 나타났다. 또한 GFRP 보강 콘크리트 보의 장기거동을 약 1년간 관찰하였으며 이로부터 FRP 보강 부재의 장기처짐 계산식에 사용되는 수정계수 값 0.73을 도출하였다. 따라서 이 연구로부터 도출된 GFRP 보강근 및 이로 보강된 콘크리트 보의 단기 및 장기 거동 특성값은 FRP 보강 콘크리트 부재의 설계에 유용하게 활용될 수 있을 것으로 사료된다.

Keywords

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