Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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Evaluation on the Bending Behavior After Yield of RC Beam by Using Image Processing Method(II): Focused on the Tensile Part

영상 분석 기법을 이용한 RC 부재의 항복 후 휨 거동 분석(II): 인장부를 중심으로

  • 김건수 (한국건설기술연구원 구조연구본부) ;
  • 박기태 (한국건설기술연구원 구조연구본부) ;
  • 우태련 ((주)파이래드)
  • Received : 2022.09.13
  • Accepted : 2022.11.01
  • Published : 2022.12.31
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Abstract

As the limit state design method is applied as a method of designing concrete structures, the ultimate state is considered in the analysis or design. In fact, when the reinforced concrete member bears tensile force, the force is transmitted from the rebar to the concrete, and the structure bears the tensile force to the ultimate state even after yield. Therefore, the accurate evaluation of behavior after yield, it is necessary to study the tension stiffening effect after yield of the flexural member. In this study, a 4-point bending test was conducted on the RC simple beam having a rectangular cross section of the double reinforcement, and the behavior of the member was analyzed in detail using the image analysis method. Using the analysis results, the estimation formula for the tension stiffening effect after yield was proposed, and the applicability of this was verified through the experimental results of existing study. The difference between the ultimate strain and the yield strain representing the ductile behavior of the member is similar to the experimental results. The prediction of the proposed formula is relatively accurate.

콘크리트구조물의 한계상태설계법이 적용되면서 구조물의 극한상태까지 고려하는 설계가 이루어지고 있다. 실제 철근콘크리트 부재가 인장력을 부담할 때 부재가 항복한 후에도 극한상태까지 콘크리트가 인장력을 부담한다. 따라서 한계상태 거동에 대한 정확한 평가를 위해서는 휨 부재의 항복 후 인장강화효과에 대한 연구가 필요하다. 본 연구에서는 복철근 직사각형 단면을 가지는 RC 단순보에 대하여 4점 휨 실험을 수행하였고, 영상분석기법을 이용하여 부재의 거동을 상세하게 분석하였다. 분석 결과를 이용하여 휨 인장강화효과 계수를 도입한 항복 후 인장강화효과 추정식을 제안하였고, 이를 기존 연구들의 실험 결과를 통해 적용성을 검증하였다. 부재의 연성거동을 대표하는 극한 변형률과 항복 변형률 차이가 실험 결과와 유사하게 나타나 제안식의 예측이 비교적 정확한 것으로 판단된다.

Keywords

Acknowledgement

본 연구는 과학기술정보통신부 한국건설기술연구원 연구운영비지원(주요사업)사업으로 수행되었습니다(과제번호20220134-001, 운송 조건이 개선된 프리캐스트 옹벽 연결부 및 프리캐스트 구조물 제작 모니터링기술 개발).

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