Evaluation of P-M Interaction Curve for Circular Concrete-Filled Tube (CFT) Column

ABSTRACTConcrete-filled tubes (CFTs) have been used in civil engineering practices as a column of buildings and a bridge pier. CFTs hav e several advantages over the conventional reinforced concrete columns, such as rapid construction, enhanced buckling resistance, and inh erited confinement effect. However, CFT component have not been widely used in civil engineering practice, since the design provisions among codes significantly vary each other. It leads to conservative design of CFT component. In this study, the design provisio ns of AISC and EC4 for CFT component were examined, based on the extensive test results conducted by previous researchers and finite element analysis results obtained in this study. Especially, the focus was made on the validation of P-M interaction curves proposed by AISC and EC4. From the results, it was found that the current design codes considerably underestimated the strength of CFT component under general combined axial load and bending. Finally, the modified P-M interaction curve was proposed and successfully verified.Key words : Concrete-filled tube (CFT), Composite structure, P-M interaction curve초 록원형 콘크리트 충전 강관(CFT)은 급속시공이 가능하고 뛰어난 좌굴 성능 및 콘크리트의 구속효과와 같은 여러 장점을 가지고 있어 , 건축물의 기둥이나 교량의 교각으로 이용되고 있다. 하지만 CFT는 이러한 장점에도 불구하고 널리 이용되고 있지 않고 있다 . 이러한 이유는 CFT의 설계 기준들이 서로 상이하여 보수적인 설계가 이루어지고 있는 것에 일부 기인한다 . 이 연구에서는 CFT설계에 널리 이용되는 AISC 및 EC4 설계 기준의 타당성을 기존 연구자들이 수행한 실험 결과 및 이 연구에서 수행된 유한요소해석 결과를 이용하여 검증하였다 . 특히 축력과 휨모멘트가 동시에 작용하는 CFT에 대하여 AISC 및 EC4에서 제안한 P-M 상관곡선의 타당성 검증에 초점을 두었다. 연구 결과, 기존의 P-M 상관곡선은 CFT의 강도를 상당히 보수적으로 예측하는 것을 알 수 있었다. 이 연구에서는 개선된 P-M 상관곡선을 제안하고 기존 실험 결과 및 이 연구에서 수행한 유한요소해석 결과를 이용하여 검증하였다.검색어 : 콘크리트 충전강관(CFT), 합성구조, P-M 상관곡선

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