Journal of Korean Society of Steel Construction (한국강구조학회 논문집)

Korean Society of Steel Construction (한국강구조학회)
권호 표지

Design Equation for Square CFT Columns with Large Width-to-Thickness Ratio

폭두께비가 큰 각형CFT 단주의 설계식

  • Received : 2009.07.14
  • Accepted : 2009.10.01
  • Published : 2009.10.27
Download PDF
⟨ Previous Next ⟩

Abstract

The design standards, such as AISC-LRFD (2005) and KBC-2005, specify the maximum width-to-thickness ratio that can be used for computing the strength of the concrete-filled tube (CFT), and do not include any formula for computing the strength when the width-to-thickness ratio is over the limit. This paper proposes a strength equation for CFTs with a large width-to-thickness ratio by acknowledging the fact that the stiffened slender steel platehas substantial postbuckling strength, and that it therefore can be more economical to use it. The equation adopts the concept of effective width,which is very useful for plate analysis. By comparing the strengths of AISC2005, KBC2005, and the proposed method with the results of the experiment, where the width-to-thickness ratio was regarded as the main parameter, the applicability of the proposed method was verified.

AISC(2005)나 KBC(2005)등의 기준에서는 콘크리트 충전 강관(Concrete Filled Steel Tube) 기둥의 내력산정에서 폭두께비의 제한을 두고 있으며 최대 폭두께비를 초과하는 기둥에 대해서는 설계식을 제시하지 않고 있다. 본 연구는 stiffened (양단지지) 플레이트에서는 좌굴이 발생하더라도 바로 내력저하가 발생하지 않고 상당한 양의 좌굴 후 강도를 발휘할 수 있어 폭두께비가 큰 강관을 사용하는 것이 경제적일 수 있다는 점을 착안, 유효폭 개념을 도입해서 폭두께비가 큰 각형 CFT의 강도를 계산할 수 있는 설계식을 제안하였다. AISC 2005, KBC 2005와 본 연구에서 제안한 식을, 폭두께비를 변수로 수행한 4개의 각형 CFT 기둥 실험결과와 비교하였며 제안된 설계식의 적용가능성을 확인하였다. 이에 Uy(2005), Dalin Liu(2005)는 폭두께비가 큰 단주 CFT에 한에서 선행 연구된 실험데이타를 근거로 제안 설계식을 단순적용 하였다. 폭두께비가 초과된 각형CFT 단주를 검토 대상기본으로 1. 용접 조립된 정사각형 단면 2. 모살용접된 정사각형 단면 (b/t 60mm. 80mm, 100mm) 3. 한 폭면의 폭두께비가 초과하는 직사각형단면의 (b/t 45.5) 실험체를 선정하여 제안식의 타당성을 검토해 보고자 한다.

Keywords

References

  1. AISC(1999) Manual of Steel Construction, AISC, Chicago, USA
  2. AISC(2005) Steel Construction Manual, Chicago, USA
  3. Dalin L. and Wie, Min Gho(2005) Axial load behaviour of high0strength rectangular concrete- filled steel tubular stub columns. Thin-walled structurares, pp.1131-1142 https://doi.org/10.1016/j.tws.2005.03.007
  4. Ge, H.B. and Usami, T.(1992) Strength of concretefilled thin-walled steel box columns: experiments. Journal of Structural Engineering, 118(11) pp.3036-3054 https://doi.org/10.1061/(ASCE)0733-9445(1992)118:11(3036)
  5. Liang Q.Q., Uy B., and Liew, R. (2006), Nonlinear analysis of concrete-filled thin-walled steel box columns with local buckling effects. Journal of construction steel research, 62, pp.581-591 https://doi.org/10.1016/j.jcsr.2005.09.007
  6. Liang, Q.Q. and Uy, B.(1998) Parametric study on the structural behaviour of steel plates in concretefilled fabricated thin-walled box columns. Advances in Structural Engineering, 2(1), pp.57-71 https://doi.org/10.1177/136943329800200108
  7. Liang, Q.Q. and Uy, B.(2000) Theoretical study on the post-local buckling of steel plates in concretefilled box columns. Computers and Structures, 75(5), pp.479-490 https://doi.org/10.1016/S0045-7949(99)00104-2
  8. Mursi, M. and Uy, B.(2003) Strength of concrete filled steel box columns incorporating interaction buckling. 129(5), pp.626-639
  9. Shanmugam, N.E. Lakshmi, B. Uy, B.(2002) An Analytical model for thin-walled steel box columns with concrete in-fill. Engineering Structures, pp.825-838
  10. Standards Australia(1999) Steel Structures, Sydney, Australia
  11. Wright, H. D.(1995) Local stability of filled and encased steel sections. Journal of Structural Engineering, 121(10), pp.1382-1388 https://doi.org/10.1061/(ASCE)0733-9445(1995)121:10(1382)
  12. Uy, B.(2000) Strength of concrete-filled steel box columns incorporating local buckling. Journal of Structural Engineering, 126(3), pp.341-52 https://doi.org/10.1061/(ASCE)0733-9445(2000)126:3(341)
  13. Uy, B. Bradford, M. A.(1995) Local buckling of thin steel plates in composite construction: Experimental and Theoretical study, Proc., Inst. Civ. Eng. Struct. Build, Vol. 110, pp.426-440 https://doi.org/10.1680/istbu.1995.28060
  14. Zhang, Y. Xu, C. and, Lu, X.(2006) HYSTERETIC BEHAVIOR OF CONCRETE FILLED THINWALLED STEEL TUBULAR COLUMNS, Steel Construction, Vol. 21, Proceedings of 8th International Conference for ASCCS, pp.202-208
  15. 강구조의 설계(2009) 한국강구조학회, 구미서관
  16. 김진호 전상우(1999) 콘크리트 충전강관 단주의 종국내력평가에 관한 실험적 연구. 한국강구조학회 논문집, Vol. 11, No. 5, pp.495-506
  17. 냉간성형강 구조설계기준 및 해설(1999) 대한건축학회
  18. 이성희, 최영환, 염경수, 김진호, 최성모(2008) 용접조립 각형 CFT 단주의 구조특성에 관한 실험적 연구. 한국강구조학회 논문집, Vol. 20, No. 5, pp.645-653