As buildings are becoming larger, demand for mega-sized composite columns (over 1-meter diameter) is increased. We have developed and commercialized welded built-up CFT column (ACT Column I) since 2005 which are structurally stable and economical using cold-formed steel with rib. However, there has a limit in size of cross section (618˟618mm) by a fabrication facilities. And due to characteristics of closed cross section, there has a limit to construction of connection of moment frame. Composite mega column (ACT Column II) has same concept of forming closed cross section. But in order to enlarge cross sectional size, thick plate is inserted between cold-formed steels. Since composite mega column can control thickness and width of thick plate, steel or composite beams can be directly attached to the connection. In this study, we propose strength formula of composite mega column to beam connections with T-shaped stiffener as internal diaphragm and verified through finite element analysis and simple tensile experiment.

1. 서 론
  1.1 연구배경 및 목적
 2. 내다이어프램 접합부 형식
  2.1 T형 스티프너 상세
 3. 합성메가기둥 접합부 내력식 제안
  3.1 내력식 제안을 위한 제한 사항
  3.2 T형 스티프너 항복내력식
  3.3 콘크리트 Cone failure 내력식
 4. T형 스티프너 항복내력식 검증을 위한유한요소해석
  4.1 유한요소해석 개요
  4.2 유한요소해석 결과
  4.3 분석 및 고찰
 5. 콘크리트와 T형 스티프너 거동 확인을위한 기둥-보 접합부 인장실험
  5.1 실험계획
  5.2 실험결과
  5.3 분석 및 고찰
 6. 결 론
 REFERENCES

• 이재현(서울시립대학교 건축공학과 석사과정, Master Degree, Department of Architectural Engineering, University of Seoul, Korea) | Lee, Jae-Hyun
• 김부규(㈜서한종합건축사사무소 전무, Executive Director, Suhhan Architects and Engineers inc., Korea) | Kim, Bu-Kyu
• 김선희(서울시립대학교 건축공학과 연구교수, Research Professor, Department of Architectural Engineering, University of Seoul, Korea) | Kim, Sun-Hee
• 염경수(㈜액트파트너 소장, Head, Act Partner, Korea) | Yom, Kyong-Soo
• 최성모(서울시립대학교 건축공학과 교수, Professor, Department of Architectural Engineering, University of Seoul, Korea) | Choi, Sung-Mo Corresponding author