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Shear Strength of Hybrid Beams Combining Precast Concrete and Cast-In-Place Concrete

프리캐스트 콘크리트와 현장타설 콘크리트 복합 보의 전단강도

  • Kim, Chul-Goo (Dept. of Architecture & Architectural Engineering, Seoul National University) ;
  • Park, Hong-Gun (Dept. of Architecture & Architectural Engineering, Seoul National University) ;
  • Hong, Geon-Ho (Dept. of Architectural Engineering, Hoseo University) ;
  • Kang, Su-Min (Researcher at Daelim Industrial Co.)
  • Received : 2012.09.13
  • Accepted : 2013.02.01
  • Published : 2013.04.30

Abstract

Currently in precast concrete construction, precast concrete and cast-in-place concrete with different concrete strengths are used. However, current design codes do not provide shear design methods for PC-CIP hybrid members using dual concrete strengths. In the present study, the shear strengths of beams using dual concrete compressive strengths (24 MPa, 60 MPa) were tested. The test variables were the area ratio of the two concretes, longitudinal bar ratio, and shear span-to-depth ratio. The shear strengths of test specimens were evaluated by current design methods, using an effective concrete strength (considering the area ratio of the two concrete strengths). The test result showed that when 60 MPa concrete was used in the compressive zone and the longitudinal bar ratio was low, the shear strengths of the test specimens were less than the predictions. On the basis of the results, design recommendations were provided for the shear design of the PC-CIP hybrid beams.

최근 다른 압축강도로 타설된 프리캐스트 콘크리트(PC)와 현장타설 콘크리트(CIP)의 복합 부재의 사용이 증가하고 있지만 현행 기준에는 서로 다른 강도로 복합화된 부재의 전단강도에 대한 설계 기준이 없다. 그래서 이번 연구에서 서로 다른 압축강도(24 MPa, 60 MPa)로 분리 타설된 보의 전단강도 실험을 수행하여 복합 부재의 전단강도에 대해 알아보았다. 변수로는 단면형상, 휨철근비, 그리고 전단경간비를 고려하였다. 실험 결과 값과 현행 전단 기준식과 단면적비로 계산한 유효 콘크리트 강도를 이용한 예측 값을 비교하였다. 실험 결과를 분석해보면 철근비가 낮고 압축대에 60 MPa가 사용된 실험체들에 대해 설계 기준식을 과대평가하였다. 실험 결과를 기준으로 PC와 CIP 복합부재의 전단설계 기준을 제안하였다.

Keywords

References

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  5. Evaluation of Horizontal Shear Strength for Concrete Composite Members vol.28, pp.4, 2016, https://doi.org/10.4334/JKCI.2016.28.4.407
  6. Shear Strength of Prestressed PC-CIP Composite Beams without Vertical Shear Reinforcements vol.26, pp.4, 2014, https://doi.org/10.4334/JKCI.2014.26.4.533