A Proposal of Minimum Steel Ratio Considering Size Effect for Flexural Reinforced Concrete Member

크기효과가 고려된 철근콘크리트 휨 부재의 최소철근비 제안

  • Yoo, Sung-Won (Department of Civil and Environmental Engineering, Woosuk University) ;
  • Her, Yoon (Korea Conformity Laboratories)
  • 유성원 (우석대학교 토목환경공학과) ;
  • 허윤 (한국건설생활환경시험연구원)
  • Received : 2010.08.05
  • Accepted : 2010.10.28
  • Published : 2010.12.31


In according with concrete structural design standard, it is common designing flexure reinforcement concrete to induce tension failure. So reinforcing ratio is limited to inducing tension failure. And maximum reinforcing ratio is regulated to protecting concrete compression strength caused by over reinforced building. Minimum reinforcing ratio is also limited in designing standard to protecting brittle failure as extremely using less reinforcing bar. But in minimum reinforcing ratio it is extremely conservative or it is sometimes impossible to induce stable tension-failure because they are depending on yield failure and experienced method and concrete designing standard strength. Therefore the purpose of the present paper is to evaluate the flexural behavior of minimum steel ratio of reinforced concrete of beams and to propose the guide-line of equation of minimum steel ratio by performing static flexural test of 16 beams according to size effect, number of steel, yielding stress of steel, and concrete compressive strength which are presumed effective variables. From experimental results, the equation of minimum steel ratio was newly proposed considered size effect.


Supported by : 우석대학교


  1. 한국콘크리트학회, "콘크리트 구조설계기준 해설", 기문당, pp. 123, 2008.
  2. 대한토목학회, "도로교 설계기준 해설", 기문당, pp. 427, 2008.
  3. 김우 외 4인, "콘크리트구조설계", 동화기술, pp. 109-110, 2005.
  4. Carpinteri, A., "Stability of Fracturing Process in RC Beams", ASCE Journal of Structural Engineering, Vol. 110, No. 3, pp. 544-558, 1984. https://doi.org/10.1061/(ASCE)0733-9445(1984)110:3(544)
  5. Baluch, M. H., A. K. and Ashmawi, W., "Fracture Mechanics Application to Reinforced Concrete Members in Flexure", Proc. Int Workshop on Application of Fracture Mechanics to Reinforced Concrete, Italy, pp. 413-436, 1992.
  6. Gerstle, W. H., Dey, P. P., N. N. V., Rahulkumar, P. and Xie, M., "Crack Growth in Flexural Members - A Fracture Mechanics Approach, Concrete", ACI Structure Journal, Vol. 89, No. 6, pp. 617-625, 1992.
  7. Bosco, C., Carpinteri, A. and Debernardi, P.G., "Minimum Reinforcement in High Strength Concrete", Journal of Structural Engg, Vol. 116, No. 2, pp. 427-437, 1990. https://doi.org/10.1061/(ASCE)0733-9445(1990)116:2(427)
  8. Bosco, C., Carpinteri, A. and Debernardi, P.G., "Fracture of Reinforced Concrete: Scale Effects and Snap-Back Instability", Engg. Frac Mech, Vol. 35, No.4/5, pp. 665-677, 1990. https://doi.org/10.1016/0013-7944(90)90149-B