Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
권호 표지
DOI QR코드

DOI QR Code

Flexural Performance of PHC Piles with Infilled concrete and Longitudinal Reinforcing Bars

속채움 콘크리트 및 길이방향 철근으로 보강된 PHC 파일의 휨성능

  • 한선진 (서울시립대학교 건축학부) ;
  • 이정민 (토론토 대학교 토목공학과) ;
  • 김민석 (서울시립대학교 건축공학과) ;
  • 김재현 (서울시립대학교 건축공학과) ;
  • 김강수 (서울시립대학교 건축공학과 스마트시티융합전공) ;
  • 오영훈 (건양대학교 의료공간디자인학과)
  • Received : 2021.03.25
  • Accepted : 2021.06.28
  • Published : 2021.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, flexural tests of prestressed high strength spun concrete (PHC) piles reinforced with infilled concrete and longitudinal rebars were conducted, where the longitudinal rebar ratio and the presence of sludge formed on the inner surface of PHC pile were set as key test variables. A total of six PHC pile specimens were manufactured, and their flexural behaviors including failure mode, crack pattern, longitudinal strain distribution in a section and end slip between external PHC pile and infilled concrete were measured and discussed in detail. The test results revealed that the flexural stiffness and strength increased as the longitudinal rebar ratio became larger, and that the sludge formed on the inner surface of PHC pile did not show any detrimental effect on the flexural performance. In addition to the experimental approach, this study presents a nonlinear flexural analysis model considering compatibility conditions and strain and stress distributions of the PHC piles and infilled concrete. The rationality of the nonlinear flexural analysis model was verified by comparing it with test results, and it appeared that the proposed model well evaluated the flexural behavior of PHC piles reinforced with infilled concrete and longitudinal rebars with a good accuracy.

이 연구에서는 속채움 콘크리트와 길이방향 철근으로 보강된 PHC 파일에 대한 휨실험을 수행하였으며, 실험의 주요 변수는 길이 방향 철근비와 PHC 파일 중공 내부 표면에 형성된 슬러지 유무로 설정하였다. 총 6개의 PHC 파일 실험체를 제작하였으며, 실험체들의 파괴모드, 균열패턴, 단면내 길이방향 변형률 분포, PHC 파일과 속채움 콘크리트 사이에 발생된 단부 슬립을 상세히 계측하고 분석하였다. 실험결과, 길이방향 철근비가 증가할수록 휨 강성 및 강도가 증가하는 것으로 나타났으며, PHC 파일 내부 표면에 형성된 슬러지는 실험체의 휨성능에 큰 영향을 미치지 않는 것으로 나타났다. 실험적 연구와 더불어 이 연구에서는 변형률 적합조건, PHC 파일과 속채움 콘크리트 단면내 변형률 및 응력 분포를 고려한 비선형 휨해석 모델을 제안하였으며, 해석결과를 실험결과와 비교하여 제안모델의 합리성을 검증하였다. 그 결과, 제안모델은 속채움 콘크리트와 길이방향 철근으로 보강된 PHC 파일의 휨거동을 매우 우수한 정확도로 평가하는 것으로 나타났다.

Keywords

Acknowledgement

이 논문은 2020년도 정부(교육과학기술부)의 재원으로 한국연구재단 지역대학우수과학자지원사업의 지원을 받아 수행되었습니다(과제번호: NRF-2020R1I1A3054759).

References

  1. Lei, M., Liu, L., Lin, Y., and Li, J. (2019), Study on Flexural Bearing Capacity Calculation Method of Enclosure Pile with Partial Excision in Deep Foundation Pit, Advances in Civil Engineering, 4812857.
  2. Yang, Z., Li, G., Wang, W., and Lv, Y. (2018), Study on the Flexural Performance of Prestressed High Strength Concrete Pile, KSCE Journal of Civil Engineering, 22, 4073-4082. https://doi.org/10.1007/s12205-018-1811-y
  3. Kim, H. J., and Mission, J. L. C. (2011), Improved evaluation of Equivalent Top-Down Load-Displacement Curve from a Bottom-up Pile Load Test, Journal of Geotechnical and Geoenvironmental Engineering, 137(6), 568-578. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000454
  4. Chung, H. J., and Paik, K. H. (2018), Analysis on Flexural Behavior of Hollow Prestressed Concrete Filled Steel Tube Piles, Journal of the Korea Institute for Structural Maintenance and Inspection, 22(2), 133-140. https://doi.org/10.11112/JKSMI.2018.22.2.133
  5. Bang, J. W., Park, C. K., Yang, S.Y., and Kim, Y. Y. (2016), Flexural Behavior of Large-Diameter Composite PHC pile Using In-Filled Concrete and Reinforcement, Journal of the Korea Institute for Structural Maintenance and Inspection, 20(5), 109-115. https://doi.org/10.11112/jksmi.2016.20.5.109
  6. Bang, J. W., Hyun, J. H., Ahn, K. C., and Kim, Y. Y. (2017), Development and Evaluation of Hollow-head Precast Reinforced Concrete Pile, Journal of the Korea Institute for Structural Maintenance and Inspection, 21(2), 130-137. https://doi.org/10.11112/jksmi.2017.21.2.130
  7. Hyun, J. H., 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 Korea Concrete Institute, 24(1), 71-78. https://doi.org/10.4334/JKCI.2012.24.1.071
  8. Kim, M. S. (2021), Flexural and Shear Strength of PHC Piles Reinforced with Infilled Concrete, Master Thesis, University of Seoul, Seoul, South Korea.
  9. Korean Industrial Standards. (2014), KSF 4306, Pretensioned spun high strength concrete piles, Korean Industrial Standards, Seoul, South Korea.
  10. Han, S. J., Jeong, J. H., Joo, H. E., Choi, S. H., Choi, S., and Kim, K. S. (2019), Flexural and Shear Performance of Prestressed Composite Slabs with Inverted Multi-Ribs, Applied Sciences, 9(22), 4946. https://doi.org/10.3390/app9224946
  11. Popovics, S. A. (1973), Numerical Approach to the Complete Stress-Strain Curve of Concrete, Cement and Concrete Research, 3(5), 583-599. https://doi.org/10.1016/0008-8846(73)90096-3
  12. Ramberg, W., and Osgood, W. R. (1943), Description of stress- strain curves bythree parameters, National Advisory Committee For Aeronautics,Technical Note No. 902, Washington DC, USA.
  13. Han, S. J., Lee, D. H., Oh, J. Y., Choi, S. H., and Kim, K. S. (2018), Flexural Responses of Prestressed Hybrid Wide Flange Composite Girders, International Hournal of Concrete Structures and Materials, 12, 53. https://doi.org/10.1186/s40069-018-0268-1
  14. Korea Concrete Institute (2017), Korea Model Code 2017 (KCI 2017), Korea Concrete Institute, Seoul, Republic of Korea.