KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Target Reliability Indices of Static Design Methods for Driven Steel Pipe Piles in Korea

국내 항타강관말뚝 설계법의 목표 신뢰도지수

  • 곽기석 (한국건설기술연구원 토질 및 기초연구실) ;
  • 허정원 (전남대학교 공학대학 건설환경공학부) ;
  • 김경준 (노스캐롤라이나 주 교통국 동부지역 지반공학부) ;
  • 박재현 (한국건설기술연구원 토질 및 기초연구실) ;
  • 이주형 (한국건설기술연구원 토질 및 기초연구실)
  • Received : 2007.08.09
  • Accepted : 2007.11.23
  • Published : 2008.01.31
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Abstract

As a part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, reliability analyses for driven steel pipe piles are performed and the target reliability indices are selected carefully. The 58 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles. The static bearing capacity formula and the Meyerhof method using N values are applied to calculate the expected design bearing capacity of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative bearing capacities with the design values. Reliability analysis was performed by two types of advanced methods: First Order Reliability Method (FORM), and Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The static bearing capacity formula exhibited relatively small variation, whereas the Meyerhof method showed relatively high inherent conservatism in the resistance bias factors. Reliability indices for safety factors in the range of 3 to 5 were evaluated respectively as 1.50~2.89 and 1.61~2.72 for both of the static bearing capacity formula and the Meyerhof method. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, based on the reliability level of the current design practice and considering redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure.

국내 기초구조물에 대한 하중저항계수설계법 개발의 일환으로 항타강관말뚝에 대한 신뢰성 수준을 평가하고 목표 신뢰도지수를 결정하였다. 국내 정재하시험 및 지반조사 자료를 수집하여 말뚝의 대표 측정 극한지지력을 결정하였고, 정역학적 지지력공식과 Meyerhof 경험식을 이용하여 설계 극한지지력을 산정하였다. 이들 자료의 비교 분석을 통해 저항편향계수를 산정하였다. 저항편향계수의 통계 특성을 이용하여 일차신뢰도법 및 몬테카를로 시뮬레이션에 의한 신뢰성 분석을 실시하였다. 정역학적 지지력공식은 자료의 변동성이 낮았고 Meyerhof 경험식은 내재적 보수성이 크게 나타났다. 안전율 3.0~5.0에 대한 신뢰도지수 분석 결과 정역학적 지지력공식은 1.50~2.89, Meyerhof 경험식은 1.61~2.72로 평가되었다. 신뢰성 분석 결과를 바탕으로 목표 신뢰도지수는 무리말뚝으로 시공되는 경우 2.0, 2.33을, 무리말뚝으로 시공되지 않는 경우 2.5의 값을 결정하였다.

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References

  1. 곽기석, 박재현, 최용규, 허정원(2006) LRFD 설계를 위한 항타강관말뚝의 저항편향계수 산정. 대한토목학회 논문집, 대한토목학회, 제26권, 제5C호, pp. 343-350
  2. 건설교통부(2001) 도로교설계기준. 대한토목학회
  3. 건설교통부(2003) 구조물기초설계기준. (사)한국지반공학회
  4. (사)한국지반공학회(1997) 지반조사결과의 해석 및 이용. 지반공학시리즈 1, 도서출판 구미서관
  5. (사)한국지반공학회(2002) 깊은기초. 지반공학시리즈 4, 도서출판 구미서관
  6. 한국건설기술연구원(2007) LRFD 기초구조물 설계를 위한 저항계수 결정 연구. 건설교통부 건설교통 R&D 정책.인프라 사업 2차년도 연구보고서, 건설교통부
  7. American Society of Civil Engineers (1997) Standard Guidelines for the Design and Installation of Pile Foundations. ASCE 20-96, ASCE, Reston, Virginia, USA
  8. American Association of State Highway and Transportation Official (AASHTO) (2007) AASHTO LRFD Bridge Design Specifications Fourth Edition. AASHTO, Washington DC
  9. Ayyub, B.M. and Assakkaf, I. (1999) LRFD Rules for Naval Surface Ship Structures: Reliabiltiy-Based Load and Resistance Factor Design Rules. Naval Surface Warfare Center, Carderock Division, U.S. Navy
  10. Barker, R.M., Duncan, J.M., Rojiani, K.S., Ooi, P.S.K., Tan, C.K., and Kim, S.C. (1991) Manual for the Design of Bridge Foundations. NCHRP Report 343, Transportation Research Board, Washington, DC
  11. Becker, D.E. (1996) Limit state design for foundations. Part I. An overview of the foundation design process. Canadian Geotechnical Journal, Vol. 33, No. 6, pp. 956-983 https://doi.org/10.1139/t96-124
  12. Goble, G. (1999) Geotechnical Related Development and Implementation of Load and Resistance Factor Design(LRFD) Methods. NCHRP Synthesis of Highway Practice 276, Transportation Research Board, Washington, D.C
  13. Haldar, A. and Mahadevan, S. (2000) Probability, Reliability and Statistical Methods in Engineering Design. John Wiley & Sons, New York, NY
  14. Hara, A., Ohata, T., and Niwa, M. (1971) Shear modulus and shear strength of cohesive soils. Soils and Foundations, Vol. 14, No. 3, pp. 1-12
  15. Hasofer, A.M. and Lind, N.C. (1974) Exact and invariant secondmoment code format. Journal of Engineering Mechanics, ASCE, Vol. 100, No. 1, pp. 111-121
  16. Huh, J. and Haldar, A. (2001) Stochastic finite-element-based seismic risk of nonlinear structures. Journal of Structural Engineering, ASCE, Vol. 127, No. 3, pp. 323-329 https://doi.org/10.1061/(ASCE)0733-9445(2001)127:3(323)
  17. Kulhawy, F. and Phoon, K. (1996) Engineering Judgment in the Evolution from Deterministic to Reliability-Based Foundation Design. Proceedings of the 1996 Conference on Uncertainty in the Gelologic Environment, UNCERTAINTY '96, Part I, Madison, WI, ASCE, NY, pp. 29-48
  18. Maurice, B., Frischknecht, R., Coelho, V., Hungerbhler (2000) Uncertainty analysis in life cycle inventory. application to the production of electricity with french coal power plants. Journal of Cleaner Production, Vol. 8, No. 2, pp. 95-108 https://doi.org/10.1016/S0959-6526(99)00324-8
  19. Meyerhof, G. (1970) Safety factors in soil mechanics. Canadian Geotechnical Journal, Vol. 7, No. 4, pp. 349-355 https://doi.org/10.1139/t70-047
  20. Nowak, A. (1999) Calibration of LRFD Bridge Design Code. NCHRP Report 368, Transportation Research Board, Washington, D.C
  21. Paikowsky, S.G. (2004) Load and Resistance Factor Design for Deep Foundations. NCHRP report 507, Transportation Research Board, Washington, D.C
  22. Rackwitz, R. and Fiessler, B. (1978) Structural reliability under combined random load sequences. Computers & Structures, Vol. 9, pp. 484-494
  23. Tang, W., Woodfor, D., and Pelletier, J. (1990) Performance reliability of offshore piles. Proceedings of the 22nd Annual Offshore Technology Conference, Offshore Technology Conference, Vol. 3, pp. 299-308
  24. Wen, Y.K. (2000) Reliability and performance based design. Proceedings of the 8th ASCE Specialty Conference on Probabilistic Mechanics and Structural Reliability: PMC 2000, University of Notre Dame
  25. Whitman, R. (1984) Evaluating calculated risk in geotechnical engineering. the 17th terzaghi lecture, Journal of Geotechnical Engineering, ASCE, Vol. 110, No. 2, pp. 2340-2356
  26. Wu, T., Tang, W., Sangrey, D., and Baecher, G. (1989) Reliability of offshore foundations-state of the art. Journal of Geotechnical Engineering, ASCE, Vol. 115, No. 2, pp. 157-178 https://doi.org/10.1061/(ASCE)0733-9410(1989)115:2(157)
  27. Zhang, L., Tang, W., and Ng, C. (2001) Reliability of axially loaded driven pile groups. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 127, No. 12, pp. 1051-1060 https://doi.org/10.1061/(ASCE)1090-0241(2001)127:12(1051)
  28. Zhang, L. (2002) Ultimate resistance of laterally loaded piles in cohesionless soils. Proceedings of the International Deep Foundations Congress: An International Perspective on Theory, Design, Construction, and Performance, Geotechnical Special Publication No. 116, ASCE, Orlando, Florida, pp. 1364-1375