Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Shear Friction Strength based on Limit Analysis for Ultra-High Performance Fiber Reinforced Concrete

소성 이론에 의한 강섬유 보강 초고성능콘크리트의 전단 마찰 강도식 제안

  • Lee, Ji-Hyung (Dept. of Architecture & Architectural Engineering, Seoul National University) ;
  • Hong, Sung-Gul (Dept. of Architecture & Architectural Engineering, Seoul National University)
  • Received : 2015.03.04
  • Accepted : 2015.04.13
  • Published : 2015.06.30
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Abstract

Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is distinguished from the normal concrete by outstanding compressive and tensile strength. Cracked normal concrete resists shear by aggregate interlocking while clamped by transverse reinforcement, which is called as shear friction theory. Cracked UHPFRC is expected to have a different shear transfer mechanism due to rather smooth crack face and post-cracking behavior under tensile force. Twenty-four push-off specimens with transverse reinforcement are tested for four different fiber volume ratio and three different ratio of reinforcement along the shear plane. The shear friction strength for monolithic concrete are suggested by limit analysis of plasticity and verified by test results. Plastic analysis gives a conservative, but reasonable estimate. The suggested shear friction factor and effectiveness factor of UHPFRC can be applied for interface shear transfer design of high-strength concrete and fiber reinforced concrete with post-cracking tensile strength.

강섬유 보강 초고성능 콘크리트(UHPFRC)는 뛰어난 압축 및 인장강도를 가지고 있는 재료이다. 일반 콘크리트는 균열 발생 후 균열에 수직으로 보강된 철근의 구속력을 수직항력으로, 구속력에 의해 발생하는 골재 맞물림 등에 의한 균열면의 거칠기를 마찰 계수로 표현하여 전단 마찰 강도를 정의하고 있다. UHPFRC는 골재 맞물림 현상은 없으나 강섬유의 부착응력에 의한 균열 후 인장력이 상당히 큰 특징이 있으며, 이러한 특징은 전단 마찰 강도에 반영되어야 함이 타당하다. 본 연구에서는 전단면에 횡철근이 보강된 24개의 직접 전단실험체를 제작하여 푸시 오프 실험을 수행하였다. 실험결과는 소성 이론에 의해 분석되었으며 이로부터 전단 마찰 계수와 유효 계수를 도출하였다. 소성 이론에 의한 전단 마찰 강도식은 기존 실험결과 및 기존 전단 마찰 강도식과 비교하여 타당성을 검증하였으며, 최종적으로 UHPFRC의 균열 후 인장강도를 고려한 일체식 구조체의 전단 마찰 강도식을 제안하였다.

Keywords

References

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