영상 분석 기법을 이용한 RC 부재의 항복 후 휨 거동 분석(II): 인장부를 중심으로 = Evaluation on the Bending Behavior After Yield of RC Beam by Using Image Processing Method(II): Focused on the Tensile Part

다국어 초록 (Multilingual Abstract)

As the limit state design method is applied as a method of designing concrete structures, the ultimate state is considered in the analysis ordesign. In fact, when the reinforced concrete member bears tensile force, the force is transmitted from the rebar to the concrete, and the structure bearsthe tensile force to the ultimate state even after yield. Therefore, the accurate evaluation of behavior after yield, it is necessary to study the tension stiffeningeffect 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 sectionof the double reinforcement, and the behavior of the member was analyzed in detail using the image analysis method. Using the analysis results, theestimation formula for the tension stiffening effect after yield was proposed, and the applicability of this was verified through the experimental resultsof existing study. The difference between the ultimate strain and the yield strain representing the ductile behavior of the member is similar to theexperimental results. The prediction of the proposed formula is relatively accurate.

국문 초록 (Abstract)

콘크리트구조물의 한계상태설계법이 적용되면서 구조물의 극한상태까지 고려하는 설계가 이루어지고 있다. 실제 철근콘크리트부재가 인장력을 부담할 때 부재가 항복한 후에도 극한상태까지 콘크리트가 인장력을 부담한다. 따라서 한계상태 거동에 대한 정확한 평가를위해서는 휨 부재의 항복 후 인장강화효과에 대한 연구가 필요하다. 본 연구에서는 복철근 직사각형 단면을 가지는 RC 단순보에 대하여 4점휨 실험을 수행하였고, 영상분석기법을 이용하여 부재의 거동을 상세하게 분석하였다. 분석 결과를 이용하여 휨 인장강화효과 계수를 도입한항복 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.

참고문헌 (Reference)

1 김건수 ; 박기태 ; 우태련 ; 김재환, "영상 분석 기법을 이용한 RC 부재의 항복 후 휨 거동 분석(I): 압축부를 중심으로" 한국구조물진단유지관리공학회 26 (26): 39-46, 2022

2 우태련 ; 정치영 ; 김인태 ; 이종한 ; 정진환, "색상에 기반한 영상분석기법을 이용한 콘크리트 거더의 휨 거동 분석" 한국구조물진단유지관리공학회 24 (24): 48-54, 2020

3 Scott, B. D., "Stress-strain behavior of concrete confined by overlapping hoops at low and high stress rate" 79 (79): 13-27, 1982

4 Lee, J. H., "Post-yielding tension stiffening of reinforced concrete nembers using an image analysis method with a consideration of steel ratios" 7 (7): 117-126, 2019

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8 Yoon. D. W., "Behavioral characteristics of RC tensile member depending on the steel ratio by using image processing method," Pusan National University 2017

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