For the safe design of steel-concrete composite structure, usable yield strength of steels are limited in most of design standard. However, this limitation sometimes cause the uneconomical design for some kind of members such as slender columns which was affected by elastic buckling load. For the economical design for slender columns, parametric study of RCFT (Rectangular CFT) with high-strength steel is conducted, especially investigating the limitation of yield strength of high-strength steels. Using ABAQUS, finite element analysis program, the finite element model was constructed and calibrated with experimental study for RCFT with high strength steel which have yield strength up to 680MPa. Investigated design parameters are yield strength of steel, compressive strength of concrete, steel thickness and slenderness ratio. The effect of desgn parameters were compared with design standard, KBC-09. From the parametric study with 54 models and previous test specimens, RCFT can be safely design with higher yield strength of steels than currently limited by KBC for large range of slenderness ratio.

1. 서 론
 2. 직사각형 콘크리트 충전 강관기둥의 설계강도
  2.1 KBC 2009
  2.2 AISC-LRFD 2010
  2.3 강도의 제한과 세장비의 영향
 3. 고강도 강재를 사용한 RCFT의 성능 평가
  3.1 실험체 계획
  3.2 실험 결과
  3.3 설계기준의 적용성 평가
 4. 유한요소해석
  4.1 유한요소모델
  4.2 유한요소 해석 모델의 검증
 5. 유한요소해석을 통한 변수분석
  5.1 변수 설정
  5.2 강재 항복강도의 영향
  5.3 판 두께의 영향
  5.4 세장비에 따른 RCFT의 좌굴 강도
 6. 결 론
 감사의 글
 References

• 최현기(정회원, 경남대학교 소방방재공학과 교수) | Hyun-Ki Choi
• 배백일(정회원, 한양대학교 산업과학연구소 POST DOC) | Baek-Il Bae 교신저자
• 최윤철(정회원, 청운대학교 건축설비소방학과 교수) | Yun-Cheol Choi
• 최창식(정회원, 한양대학교 건축공학부 교수) | Chang-Sik Choi