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2019 Vol.35, Issue 12 Preview Page

Research Article

Proposed Deterioration-induced Axial Stiffness of Existing Piles in Vertical Extension Structures

수직증축 공동주택 하부 기존말뚝의 열화를 고려한 축강성 제안

Sang-Seom Jeong1
,
Do-Hyun Kim2*
,
Hyun-Chul Cho3
정 상섬1
,
김 도현2*
,
조 현철3
1Member, Prof., Dept. of Civil and Environment Engrg., Yonsei Univ.
2Member, Post-doctoral Researcher, Dept. of Civil and Environmental Engrg., Massachusetts Institute of Technology
3Member, Hyundai Engineering and Construction
1정회원, 연세대학교 건설환경공학과 교수
2정회원, 매사추세츠 공과대학 토목환경공학과 박사 후 연구원
3정회원, 현대엔지니어링 사원
* Corresponding Author
31 December 2019. pp. 25-33
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Abstract

본 연구에서는 수직증축 구조물의 기존말뚝의 축강성(Kve)을 이론적인 접근과 현장 계측 결과를 바탕으로 추정하였다. 이론적인 접근에는 Randolph와 Wroth(1978)가 제안한 축강성 공식을 적용하여, 지중에 설치된 강성 및 연성말뚝의 세장비(L/D)에 따른 축강성의 범위를 도출하였다. 여기에, 1995 – 1997년 사이에 설치된 38본 말뚝의 계측된 시공 당시 축강성을 이론적으로 도출한 축강성 범위에 중첩해서 고려하였다. 이를 통하여, 노후화와 열화에 의하여 감소한 기존말뚝의 축강성의 최대값을 세장비에 따라 제안하였고, 도출된 값을 통계적인 기법을 통하여 상위 95% 값을 제안하여 신설 보강말뚝 설계 시 필요한 최소 축강성(Kvr)을 산정하는 데에 활용할 수 있도록 하였다.

In this study, the axial stiffness of existing piles (Kve) of vertical extension remodeled building was quantified through theoretical and experimental approaches. Theoretically induced upper and lower boundary of the pile axial stiffness was estimated by using the formula proposed by Randolph and Wroth (1978), which can estimate the axial stiffness of rigid and flexible pile subjected under soil confinement. In addition, 38 cases of field measurement data on deteriorated piles with various diameters constructed in the period between 1995 – 1997 were taken in to account by overlapping the field data with the theoretical boundary of the axial stiffness. Through this the maximum axial stiffness of existing pile due to deterioration and long service time was presented for various slenderness ratio (L/D), which can be used in estimating the necessary axial stiffness of reinforcing piles(Kvr) for the vertical extension remodeling. The lower 95% value of the estimated axial stiffness of existing pile will be induced through statistical processing.

Keywords
Axial stiffness
Field measurements
Pile deterioration
Piled-raft foundation
Reinforcing pile
Vertical extension remodeling

References
1
Cho, H. (2019), A Study on the Axial Stiffness and Load Distribution Ratio on Existing and Reinforcing Piles in Vertical Apartment Extension, Master thesis, Yonsei University, Seoul, Korea.
2
Choi, C.H., Lee, H.J., Choi, K.S., You, Y.C., and Kim, J.Y. (2017), "A Study of Prestressed Concrete Pile Stiffness for Structural Analysis of Condominium Remodeling with Vertical Story Extension", Journal of the Korean Geotechnical Society, Vol.33, No.12, pp.81-92.
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Kim, D. H., Kim, J. H., and Jeong, S. S. (2019), "Estimation of Axial Stiffness on Existing and Reinforcing Piles in Vertical Extension Remodeled Buildings", Engineering Structures,
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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 35
  • No :12
  • Pages :25-33
  • Received Date : 2019-08-19
  • Revised Date : 2019-11-06
  • Accepted Date : 2019-11-07
  • DOI :https://doi.org/10.7843/kgs.2019.35.12.25
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