한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

  • 제35권12호
  • /
  • Pages.91-100
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  • 2019
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  • 1229-2427(pISSN)
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  • 2288-646X(eISSN)
한국지반공학회 (Korean Geotechnical Society)
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긴장력이 도입된 중공형 콘크리트 충전 강관말뚝의 휨강도 산정

Estimation of Flexural Strength of Hollow Prestressed Concrete Filled Steel Tube Piles

  • 백규호 (가톨릭관동대학교 토목공학과)
  • Paik, Kyu-Ho (Dept. of Civil Engrg., Catholic Kwandong Univ.)
  • 투고 : 2019.10.21
  • 심사 : 2019.11.18
  • 발행 : 2019.12.31
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초록

수평하중에 대한 휨강성을 증대시키기 위해 얇은 두께의 강관 내부에 PHC말뚝을 합성한 중공형 콘크리트 충전강관(HCFT)말뚝을 개발하였고, HCFT말뚝의 현장 적용 시 말뚝의 구조안전성 평가에 필요한 한계상태에서 P-M 상관도를 작도할 수 있는 산정식을 제안하였다. HCFT말뚝을 구성하는 강관과 PC강봉에 대한 강도 값으로 항복응력을 적용할 경우 제안식은 HCFT말뚝의 극한휨내력을 큰 폭으로 과소평가하였고, 축력이 작용하지 않을 때 휨강도시험결과와 달리 HCFT말뚝보다 직경이 동일하고 두께가 12mm인 강관말뚝의 극한휨내력을 더 크게 산정하였다. 그러나 HCFT말뚝을 구성하는 강관과 PC강봉에 대해 항복강도인 fy 대신 극한강도인 fu를 사용하면 제안식은 휨강도시험 측정결과에 매우 근접한 극한휨내력을 제공하는 것으로 나타났다.

Hollow prestressed concrete-filled steel tube (HCFT) piles, which combines PHC piles inside thin-wall steel tubes, were developed to increase the flexural strength of the pile with respect to the lateral load. Since P-M curves are needed for evaluating the structural safety of piles when applying HCFT piles to fields, equations for plotting P-M curves of HCFT piles in limit states were proposed. When the yield strength is applied to the steel tube and PC steel bar of HCFT piles, the proposed equations significantly underestimated the flexural strength of HCFT piles. Unlike the flexural strength test results, the proposed equations also provide greater flexural strengths for 12 mm thick steel pipe piles with the same diameter than for HCFT piles. However, when the ultimate strengths are used instead of the yield strengths for the steel tube and PC steel bar, the proposed equations provide the flexural strengths very close to the flexural strength test results.

키워드

참고문헌

  1. Bang, J.W., Hyun, J.H., Lee, B.Y., Lee, S.S., and Kim, Y.Y. (2013), "Flexural Strength of PHC Pile Reinforced with Infilled Concrete, Transverse and Longitudinal Reinforcements", Journal of the Korea Concrete Institute, Vol.25, No.1, pp.91-98. https://doi.org/10.4334/JKCI.2013.25.1.091
  2. Chin, W. J., Kang, J. Y., Choi, E. S., and Lee, J. W. (2009), "A Study on the Flexural behavior of Concrete Filled Steel Tube Girder in Parametrically Varied Filling and Composition", Journal of the Korean Society of Civil Engineers, Vol.29, No.2A, pp.109-118.
  3. Hyun, J.W., Bang, J.W, Lee, S.S., and Kim, Y.Y. (2012), "Shear Strength Enhancement of Hollow PHC Pile Reinforced with Infilled Concrete and Shear Reinforcement", Journal of the Korean Society of Civil Engineers, Vol.24, No.1, pp.71-78.
  4. Kang, H. K., Lee, C. H., and Rha, C. S. (2011), "Flexural Strength on Concrete-filled Steel Tubular Members Subjected to Pure Bending Moment", Journal of Architecture Institute of Korea, Vol.27, No.4, pp.11-21.
  5. KIBSE (2015), Korea highway bridge design code (Limit state design) commentary, Korean Institute of Bridge and Structural Engineers.
  6. KS D 3505 (2019), Steel bars for prestressed concrete, 35p.
  7. KS F 4306 (2014), Pretensioned spun high strength concrete piles, 53p.
  8. KGS (2015), Structural foundation design code commentary, Korean Geotechnical Society, 894p.
  9. KSSC (2014), Steel structure design code by load and resistance factor design, Korean Society of Steel Construction, 463p.
  10. Paik, K. H. (2018), "Strength Characteristics of Hollow Prestressed Concrete Filled Steel Tube Piles for Hybrid Composite Piles", Journal of the Korean Geotechnical Society, Vol.34, No.1, pp. 37-46. https://doi.org/10.7843/kgs.2018.34.1.37
  11. Piletech, Doosan Heavy Industries & Const., Hanmac Eng., and Korea Eng. Consultants (2008), Design and construction methods of bored hybrid composite pile that joins steel pipe and PHC piles using coupler, New Excellent Technology No. 556.
  12. WSDOT (2012), Structural design recommendations of CFT and RCFT for bridge foundation, Washington State DOT Design Memorandum, 30p.
  13. Zhan, Y., Zhao, R., Ma, Z. J., and Song, R. (2016), "Behavior of Prestressed Concrete-filled Steel Tube (CFST) Beam", Engineering Structures, Vol.122, pp.144-155. https://doi.org/10.1016/j.engstruct.2016.04.050