KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
권호 표지
DOI QR코드

DOI QR Code

Analysis of Optimized Column-pile Length Ratio for Supplementing Virtual Fixed Point Design of Bent Pile Structures

단일 현장타설말뚝의 가상고정점 설계를 보완한 상부기둥-하부말뚝 최적 길이비 분석

  • 정상섬 (연세대학교 사회환경시스템공학부) ;
  • 김재영 (연세대학교 사회환경시스템공학부)
  • Received : 2013.05.08
  • Accepted : 2013.06.29
  • Published : 2013.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the virtual fixed point analysis and 3D fully modeling analysis for bent pile structures are conducted by considering various influencing factors and the applicability of the virtual fixed point theory is discussed. Also, the optimized column-pile length ratio is analyzed for supplementing virtual fixed point design and examining a more exact behavior of bent pile structures by taking into account the major influencing parameters such as pile length, column and pile diameter, reinforcement ratio and soil conditions. To obtain the detailed information, the settlement and lateral deflection of the virtual fixed point theory are smaller than those of 3D fully modeling analysis. On the other hand, the virtual fixed point analysis overestimates the axial force and bending moment compared with 3D fully modeling analysis. It is shown that the virtual fixed point analysis cannot adequately predict the real behavior of bent pile structures. Therefore, it is necessary that 3D fully modeling analysis is considered for the exact design of bent pile structures. In this study, the emphasis is on quantifying an improved design method (optimized column-pile length ratio) of bent pile structures developed by considering the relation between the column-pile length ratio and allowable lateral deflection criteria. It can be effectively used to perform a more economical and improved design of bent pile structures.

본 연구에서는 단일 현장타설말뚝의 가상고정점을 고려한 해석과 기둥-말뚝을 3차원 전체 모델링한 해석을 비교 분석하여 가상고정점 해석법의 적정성을 평가하였다. 또한, 말뚝 길이, 기둥 및 말뚝 직경, 철근비, 지반조건 등 주요 영향인자에 따라 단일 현장타설말뚝의 거동 평가를 수행하였으며, 이를 통해 가상고정점 해석을 보완한 최적 기둥-말뚝 길이비를 분석하였다. 본 연구결과, 가상고정점을 고려한 해석은 전체 모델링한 해석과 비교하여 침하량과 수평변위를 작게 예측하였으나, 반대로 축력과 휨모멘트는 가상고정점을 고려한 해석에서 크게 나타났다. 따라서 가상고정점을 통한 해석법은 실제 구조물 거동과 다른 단부조건으로 단일 현장타설말뚝의 정확한 거동을 파악하기엔 무리가 있음을 알 수 있었으며, 이에 단일 현장타설말뚝의 정확한 설계를 위해서는 3차원 전체 모델링한 해석이 필요한 것으로 판단되었다. 또한 본 연구에서는 하부 말뚝 길이와 말뚝의 허용 수평변위 관계를 통해 최적 기둥-말뚝 길이비를 분석하였으며, 이를 통해 가상고정점을 고려한 설계를 다소 보완한 경제적이고 개선된 단일 현장타설말뚝 설계를 수행할 수 있을 것으로 기대되었다.

Keywords

References

  1. AASHTO (2002). Standard specification for highway bridges, American Assocication of State Highway and Transportation Official.
  2. Ahn, S. Y. (2010). Propesed new design method of the pile bent structure considering plastic hinge, Ph. D. Thesis, Yonsei University (in Korean).
  3. Broms, B. (1964a). "Lateral resistance of piles in cohesive soils." Journal of Geotechnical and Geoenvirment Engineering, ASCE, Vol. 90, No. 4, pp. 27-63.
  4. Broms, B. (1964b). "Lateral resistance of piles in cohesive soils." Journal of Geotechnical and Geoenvirment Engineering, ASCE, Vol. 90, No. 4, pp. 123-156.
  5. California Department of Transportation Division of Engineering Services (2006) Caltrans seismic design criteria (Version 1.4).
  6. Chai, Y. H. (2002). "Flexural strength and ductility of extended pile-shafts. I: Analytical Model." Journal of Structural Engineering, Vol. 128, No. 5, pp. 586-594. https://doi.org/10.1061/(ASCE)0733-9445(2002)128:5(586)
  7. FB-MultiPier (2012). User's manual: Ver. 4, Ensoft Inc.
  8. FHWA (1987). Drilled shaft, National Highway Institute.
  9. Hutchinson, T. C., Boulanger, R. W., Chai, Y. H. and Idriss, I. M. (2002). Seismic design and retrofit of bridges, John Wiley & Sons, New York, USA.
  10. Jeon, K. S., Kim, K. S. and Kim, J. Y. (2006). "Design and consturction of single drilled shaft foundation." Korean Geotechnical Engineer conference, pp. 86-100 (in Korean).
  11. Jeong, S. S., Kwak D. O. and Ahn, S. Y. (2005). "Analysis of Pile-Bent(CIDH Shaft/Column) structure subjected to lateral loading." Korean Society of Civil Engineers conference, pp. 3968-3971 (in Korean).
  12. Jeong, S. S., Ahn, S. Y., Kwak D. O. and Lee, J. K. (2006). "A study on the lateral behavior of pile-bent structures with p-$\Delta$ effect." Journal of Korean Geotechnical Society, Korean Geotechnical Society, Vol. 22, No. 8, pp. 77-88 (in Korean).
  13. Jeong, S. S., Kim, Y. H. and Kim, J. Y. (2011). "Influence on lateral rigidity of offshore piles using proposed p-y curves." Journal of Ocean Engineering 38, pp. 397-408. https://doi.org/10.1016/j.oceaneng.2010.11.007
  14. John, W. (2001). Cyclic large deflection testing of shaft bridges, Report No. 59A0183, University of California, Los Angeles.
  15. Kerop, D. J. (2001). Interaction between soil and full scale drilled shaft under cyclic lateral load, Ph. D. Thesis, University of California, Los Angeles.
  16. Kim, S. k., Yea, G. G., Kim, G. S. and Choi, Y. K. (2008). "A case study on horizontal displacement characteristics for single drilled shaft foundation." Korean Society of Civil Engineers conference, pp. 2017-2020 (in Korean).
  17. Kim, J. Y., Hwang, T. J. and Jeong, S. S. (2011). "Simplified analysis of pile bent structures and minimum reinforcement ratio." Journal of Korean Geotechnical Society, Korean Geotechnical Society, Vol. 27, No. 5, pp. 33-43 (in Korean). https://doi.org/10.7843/kgs.2011.27.5.033
  18. Kim, Y. H. and Jeong, S. S. (2011). "Analysis of soil resistance on laterally loaded piles based on 3D soil-pile interaction." Computers and Geotechnics, Vol. 38, No. 2, pp. 248-257. https://doi.org/10.1016/j.compgeo.2010.12.001
  19. Korea Expressway Corporation (2004). Design Criteria for Pile Bent Structure, Vol. 68, pp. 14-27 (in Korean).
  20. Lee, J. H. and Yang, J. H. (2004). "New Concrete Bridge Column System." Journal of the Korea concrete institute, Vol. 16, No. 2, pp. 24-30 (in Korean).
  21. Matlock, H. (1970). "Correlation for design of laterally loaded piles in soft clay." The second annual offshore technology conference, Houston, TX, pp. 577-607.
  22. Ministry of Land, Infrastructure and Transport (2008). Design criteria for highway bridges (in Korean).
  23. O'Neill, M. W. and Gazioglu, S. M. (1984). "Evaluation of p-y relationships in cohesive soils." Proceedings of a Analysis and Design of Pile Foundations, ASCE Geotechnical Engineering Division, 192-213.
  24. PLAXIS 3D Foundation (2008). PLAXIS 3D foundation user manual: Version 2.0. Brinkgreve, R.B. and Swolfs, W. M., PLAXIS Inc.
  25. Poulos, H. G. (1971a). "Behavior of laterally loaded piles : Part 1 - Single Piles." Journal of Soil Mechanics and foundation Div., ASCE, Vol. 97, No. 5, pp. 771-731.
  26. Poulos, H. G. (1971b). "Behavior of laterally loaded piles : Part 2 - Group piles." Journal of Soil Mechanics and foundation Div., ASCE, Vol. 97, No. 5, pp. 733-751.
  27. Reese, L. C. and Wright, W. (1977). Drilled shaft manual, U. S. Department of Transportation.
  28. Son, H. S., Choi, I. K., Kang, D. O. and Yang, J. H. (2005). "Design of single column drilled pier foundation in incheon bridge viaduct." Korean Society of Civil Engineers Conference, pp. 959-962 (in Korean).
  29. Son, H. S., Choi, I. K., Lee, S. H. and Yang, J. H. (2006). "Seismic analysis and reinforcement details of integral pile shaft-column foundations." Journal of Earthquake Engineering Society of Korea, pp. 300-307 (in Korean).
  30. Sung, C. G. (2008). Analysis of lateral behavior of pile-bent structure subjected to change of pier's cross-sectional area, Master Thesis, Yonsei University (in Korean).