Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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An Examination of the Maximum Steel Ratio for Reinforced Concrete Flexural Members: Focused on Singly Reinforced Beam with Rectangular Cross-section

철근콘크리트 휨부재의 최대철근비에 대한 고찰: 단철근 직사각형보를 중심으로

  • Lee, Jun-Seok (Biohousing Research Institute, Chonnam National University) ;
  • Kim, Woo (Dept. of Civil Engineering, Chonnam National University) ;
  • Choi, Seung-Won (Dept. of Civil and Construction, Chosun College of Science & Technology)
  • 이준석 (전남대학교 바이오하우징연구센터) ;
  • 김우 (전남대학교 토목공학과) ;
  • 최승원 (조선이공대학교 토목건설과)
  • Received : 2016.12.05
  • Accepted : 2017.01.24
  • Published : 2017.04.30
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Abstract

The design provisions for the maximum steel ratio in reinforced concrete flexural members is normally provided to ensure sufficient ductility and economy by steel yielding at member failure. In the Concrete Structural Design Code (2012), the maximum steel ratio is expressed in terms of a net strain in tensile steel, and leading to very high steel ratio in the case of using high strength materials. Thereby, this may result in difficulty to satisfy a required workability at concrete placing. On the contrary, in the Korean Highway Bridge Design Code (Limit State Design) the maximum steel ratio is given in terms of the maximum neutral axis depth ratio that is 0.4. From these results, a rational model for the maximum steel ratio is suggested so as to satisfy a ductility as well as a workability.

철근콘크리트 휨 부재의 최대철근비에 대한 설계 규정은 일반적으로 부재 파괴 시 철근이 항복하도록 하여 충분한 연성과 경제성을 보장 하도록 하고 있다. 콘크리트구조기준(2012)에서 최대철근비는 인장 철근의 순인장변형률 항으로 표현되고, 고강도 재료가 사용되는 경우 매우 높은 철근비를 나타낸다. 따라서 이는 콘크리트 타설시 시공성 확보에 어려움을 야기할 수 있다. 이에 반해, 도로교설계기준(한계상태설계)에서는 최대중립축 깊이비가 0.4가 되도록 최대철근비를 규정하고 있다. 이 결과로부터 시공성 및 연성을 확보할 수 있는 최대철근비에 대한 합리적인 모델을 제시하였다.

Keywords

References

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