Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
권호 표지
DOI QR코드

DOI QR Code

Strength Characteristics of Hollow Prestressed Concrete Filled Steel Tube Piles for Hybrid Composite Piles

복합말뚝용 중공형 콘크리트 충전 강관말뚝의 강도 특성

  • Paik, Kyu-Ho (Dept. of Civil Engrg., Catholic Kwandong Univ.)
  • 백규호 (가톨릭관동대학교 토목공학과)
  • Received : 2017.11.21
  • Accepted : 2017.12.14
  • Published : 2018.01.31
Download PDF
⟨ Previous Next ⟩

Abstract

Hollow prestressed concrete filled steel tube (HCFT) piles, which compose hollow PHC piles inside thin wall steel tubes, are developed. In order to investigate the strength characteristics of HCFT piles, flexural and shear tests were conducted on HCFT piles as well as PHC and steel pipe piles with the same diameter. Results of the test program showed that the flexural strength of HCFT piles was 2.88 and 1.19 times those of ICP and steel pipe piles with thickness of 12 mm, respectively, and its shear strength was 2.40 times that of steel pipe piles. The shear key attached to the inside of thin wall steel tube did not affect the flexural behavior of HCFT piles. It was also observed that the flexural strengths of HCFT piles with diameters of 450 and 500 mm were 35 to 63% higher than the sum of the flexural strengths of its components, respectively, because the strength of concrete in compressive zone increased by confining effect of thin wall steel tube on concrete. HCFT piles used as upper piles in hybrid composite piles might decrease the lateral displacement and increase the structural safety of structures subjected to lateral loads.

얇은 두께의 강관 내부에 PHC말뚝을 합성해서 기존 PHC말뚝 및 강관말뚝보다 휨강도와 전단강도가 향상된 프리스트레스를 도입한 중공형 콘크리트 충전 강관(HCFT)말뚝을 개발하였다. HCFT말뚝의 강도특성을 조사하기 위해 다양한 조건에서 제작된 HCFT말뚝과 함께 동일 직경의 PHC말뚝 및 강관말뚝에 대해 휨강도 및 전단강도시험을 실시하였다. 시험결과 직경이 450~500mm인 HCFT말뚝은 동일 직경의 ICP말뚝 대비 2.88배, 두께 12mm의 강관말뚝 대비 1.19배의 휨강도를 발휘하였고, 강관말뚝의 2.40배에 달하는 전단강도를 발휘하였다. 그리고 HCFT말뚝의 강관 내벽에 설치한 전단연결재는 HCFT말뚝의 휨거동에 거의 영향을 주지 않았으며, HCFT말뚝의 휨강도는 HCFT말뚝을 구성하는 강관과 PHC말뚝에 대한 개별 휨강도 합산치보다 35~63% 컸는데 이것은 강관의 구속효과로 인해 압축영역에 있는 콘크리트의 강도가 증가하기 때문으로 판단된다. 또한 HCFT말뚝이 복합말뚝에서 상부말뚝으로 사용되면 수평하중을 받는 구조물의 수평변위 저감과 구조안정성 향상에 효과적일 것으로 사료된다.

Keywords

References

  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. Elchalakani, M., Zhao, X. L., and Grzebieta, R. (2004), Concretefilled Steel Circular Tubes Subjected to Constant Amplitude Cyclic Pure Bending", Engineering Structures, Vol.26, pp.2125-2135. https://doi.org/10.1016/j.engstruct.2004.07.012
  4. 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.
  5. Kang, H. K., Lee, C. H., and Rha, C. S. (2011), "Flexural Strength of Concrete-filled Steel Tubular Members Subjected to Pure Bending Moment", Journal of Architectural Institute of Korea, Vol.27, No.4, pp.11-21.
  6. KS F 4306 (2003), Pretensioned Spun High Strength Concrete Piles, 53p.
  7. Lee, S. Y., Park, D. Y., Lee, S. B., and Lee, R. C. (2009), "Bending Performance Evaluation of Concrete Filled Tubular Structures with Various Diameter-thickness Ratios and Concrete Strengths", Journal of the Korea Institute for Structural Maintenance Inspection, Vol.13, No.2, pp.223-230.
  8. Nakamura, S., Tanaka, H., and Kato, K. (2009), "Static Analysis of Cabled-stayed Bridge with CFT Arch Ribs", Journal of Constructional Steel Research, Vol.65, pp.776-783. https://doi.org/10.1016/j.jcsr.2008.05.005
  9. Piletech, Korea Eng. Consultants, Hanmac Eng., and Doosan Heavy Industries & Const. (2008), Design and Construction Methods of Bored Hybrid Composite Pile that Joins Steel Pipe and PHC Piles Using Coupler, New Excellent Technology No.556.