Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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An Experimental Study for Bond Characteristics of Deformed Bar Embedded in Donut Type Biaxial Hollow Slab

도넛형 이방향 중공슬래브의 부착특성에 관한 실험적 연구

  • Chung, Joo-Hong (Dept. of Sustainable Architectural Engineering, Hanyang University) ;
  • Kang, Sung-Hoon (Dept. of Sustainable Architectural Engineering, Hanyang University) ;
  • Lee, Seung-Chang (R&D Center Samsung C&T Corporation) ;
  • Choi, Chang-Sik (Dept. of Architectural Engineering, College of Engineering, Hanyang University) ;
  • Choi, Hyun-Ki (The Research Institute of Industrial Science, Hanyang University)
  • 정주홍 (한양대학교 대학원 건축환경공학과) ;
  • 강성훈 (한양대학교 대학원 건축환경공학과) ;
  • 이승창 (삼성물산(주) 기반기술연구소) ;
  • 최창식 (한양대학교 건축공학과) ;
  • 최현기 (한양대학교 산업과학연구소)
  • Received : 2012.08.17
  • Accepted : 2012.12.10
  • Published : 2013.04.30
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Abstract

This study investigated the bond characteristics of embedded deformed steel bar in donut type biaxial hollow slabs. The donut type hollow sphere make concrete inner cover formed between steel bar and hollow sphere due to the hollow shape and arrangement. Generally, inner cover was thinner than outer cover, and some part of donut type biaxial hollow slab has smaller inner cover thickness than $2.5d_b$. It was affected to the bond condition of deformed bar. Furthermore, inner cover thickness changes along the longitudinal deformed bar due to hollow shape. Therefore, donut type hollow slab was divided 3 regions according to the hollow shape such as insufficient region, transition region, sufficient region. Pull-out test were performed to find out the effect of bond condition by the region. Main parameters are inner cover thickness, embedded length and bond location. Bond characteristics of donut type biaxial hollow slab were confirmed through comparison of bond stress-slip relationship, maximum bond strength and bond stress distribution of each regions. And the calculation method of bond strength of donut type biaxial hollow slab was suggested based on the test results.

이 연구는 도넛형 이방향 중공슬래브에 매입된 이형철근의 부착특성 및 부착강도 산정을 위한 기초적인 연구이다. 도넛형 이방향 중공슬래브의 철근 부착특성 및 부착강도 산정을 위해 pull-out test를 수행하였다. 도넛형 중공형성체는 슬래브 내부에 배치되어 철근과 중공형성체 사이에 내부의 피복이 형성된다. 이러한 내부피복두께는 외부피복두께보다 상대적으로 작은 피복두께를 가지며 중공형상에 따라 $2.5d_b$보다 작은 내부피복두께가 형성되기 때문에 철근의 부착에 영향을 미치게 된다. 또한 중공형성체가 일정 간격으로 떨어져 배치되어 있으므로 인장철근을 감싸고 있는 피복두께의 조건이 철근의 길이방향으로 변하게 된다. 따라서 도넛형 이방향 중공슬래브의 부착특성을 알아보기 위해서 중공형성체 형상에 따라 부착구간을 구분하였다. 구간별로 내부피복두께에 따른 부착응력-슬립 관계를 확인하였으며, 중공형성체 전 구간에 걸친 부착응력분포를 확인하여 철근의 길이방향에 따른 부착응력의 발현정도를 확인하였다. 또한 구간별 부착응력-슬립 관계를 기반으로 하여 도넛형 중공슬래브의 부착강도를 산정할 수 있는 부착강도 산정 방법을 제안하였다.

Keywords

References

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