Journal of Korean Society of Steel Construction (한국강구조학회 논문집)

Korean Society of Steel Construction (한국강구조학회)
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Axial Loading Behaviors of Square Concrete-Filled Tubular Columns with Large Width-to-Thickness Ratio Retrofitted using Carbon Fiber Reinforced Polymer Sheets(CFRP Sheets)

탄소섬유쉬트(CFRP Sheets)로 보강된 폭두께비가 큰 콘크리트 충전 각형강관 기둥의 중심축하중거동

  • Park, Jai Woo (Korea Infrastructure Safety Corporation, Research Division) ;
  • Yoo, Jung Han (School of Architecture, Seoul National University of Science & Technology)
  • 박재우 (한국시설안전공단, 시설안전연구소) ;
  • 유정한 (서울과학기술대학교, 건축학부)
  • Received : 2013.06.18
  • Accepted : 2014.05.22
  • Published : 2014.06.27
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Abstract

This paper presents the experimental results of behavior of square CFT columns with large the width-ro thickness ratio strengthened with carbon fiber reinforced polymers (CFRP) sheets subjected to concentrated axial loading. The main parameters were b/t ratio and the number of CFRP layers and 6 specimens were fabricated. The values of b/t were ranged from 60 to 100. From the tests, Maximum increase of 16% was also achieved in axial-load capacity with three transverse layered CFRP applied on four sides of steel tubes. The load capacity decreased up to 41% comparing with nominal load capacity of unstrengthened CFT column. However, for CFRP strengthened CFT, the load capacity decreased up to 32%. Finally, from the load-strain relationships, the local buckling occurred before yield point of steel tubes. Also, from the load-strain relationships, it was observed that local buckling were delayed on CFT columns by CFRP sheets retrofitting.

본 연구에서는 콘크리트 충전 각형강관 (CFTP) 단주기둥에 CFRP 쉬트를 횡방향으로 보강하고 중심축하중 실험을 수행하였다. 실험변수는 b/t, CFRP쉬트 보강겹수이며, 총 6개의 실험체가 제작되었다. 실험변수로 사용된 판폭두께비는 b/t는 60, 80, 100이고 CFRP쉬트는 3겹 보강하였다. 실험결과 판폭두께비 100 실험체에서 CFRP쉬트 3겹 보강을 통해 내력을 16% 상승시켜 보강효과를 검증하였다. 내력 저하율을 검토한 결과 국부좌굴이 발생하지 않는 단면강도를 기준으로 최대 41%정도 내력이 저하되었으나, CFRP보강을 통해 32% 정도의 내력이 저하되어 보강효과를 검증할 수 있었다. 하중-변형를 관계를 보면 강재는 항복강도 이전에 국부좌굴이 발생하였으며, CFRP쉬트의 보강을 통해 국부좌굴을 지연시킴을 확인하였다.

Keywords

References

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