The minimum reinforcement ratio is an important design factor to prevent a brittle failure in RC flexural members. A minimum reinforcement ratio is presented by assuming an effective depth of cross-section and moment arm lever in CDC and KHBDC. In this study, it suggests that a rational method for minimum reinforcement ratio is calculated by material model and force equilibrium. As results, a minimum reinforcement ratio using a p-r curve in KHBDC is evaluated about 52~80% of recent design code’s value and it induces an economical design. And also, a ductility capacity in case of placing this minimum reinforcement amount is evaluated about 89% of recent design code’s value, but ductility in a member is 7 or more, so it has a sufficient ductility capacity. Therefore, it is judged that a minimum reinforcement ratio using p-r curve has a theoretical rationality, safety and economy in a flexural member design.

Abstract
 1. 서 론
 2. 설계기준에 따른 최소철근비 및 재료모델을 통한 최소철근비
 3. 각 설계기준별 최소철근비 변수해석
  3.1 해석 대상 및 해석 변수
  3.2 각 설계기준에 따른 최소철근비 해석 결과
 4. 휨부재의 연성도 평가 및 최소철근비 제안
  4.1 해석 대상 및 해석 변수
  4.2 변위연성도 산정 및 해석 결과
  4.3 최소철근비의 제안
 5. 결 론
 References

• 최승원(조선이공대학교 조교수) | Seung-Won Choi Corresponding author