Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Assessments of Creep Properties of Strip Type fiber Reinforcement

띠형 섬유보강재의 크리프 특성 평가

  • 전한용 (전남대학교 응용화학공학부) ;
  • 유중조 (보강기술(주) 기술연구소) ;
  • 김홍택 (홍익대학교 공과대학 토목공학과) ;
  • 김경모 (보강기술(주) 기술연구소) ;
  • 김영윤 (보강기술(주) 기술연구소)
  • Published : 2003.04.01
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Abstract

Geosynthetic reinforced earth wall was introduced about 20 years ago and many structures have been constructed. Especially, segmental concrete panel facing and friction tie system are the most popular system in Korea, and this friction tie was composed of high tenacity PET filament and LDPE(Low Density Polyethylene) sheath. Due to the lack of direct-test results, design coefficients of friction tie (creep reduction factor) had been determined by quoting the previous and the foreign reference data. This is an unreasonable fact for the use of friction ties. In this study, the creep tests were performed to evaluate the creep behavior of friction tie, and the reduction factor of creep was calculated for the correct design of geosynthetic reinforced earth retaining walls. From the test results, finally it was found that the allowable creep strength of friction tie is 60% of Tult during service life, and creep reduction factor is 1.67 for each grade of friction ties.

국내에 보강토 옹벽이 도입된지 20여 년이 다 되어가고, 많은 구조물들이 시공되었다. 특히, 콘크리트 패널식 전면체와 섬유보강재를 적용하는 시스템은 국내에 가장 널리 알려진 공법이다. 이 공법의 섬유보강재는 고강도 폴리에스테르 섬유와 LDPE 피복층을 갖는 구조를 가지고 있으며, 섬유보강재를 이용한 설계에서는 몇가지 합리적이지 못한 부분이 존재해 왔다. 설계인자의 결정이 선행된 외국데이터를 기준으로 하여 간접적인 방법에 의해 이루어졌으며 보강재의 장기크리프 거동에 대해서도 마찬가지로 인용된 자료를 이용하여 왔다. 따라서 본 연구에서는 실내시험을 통하여 직접적으로 섬유보강재의 설계인자를 도출하고자 하였으며, 그 결과, 설계연한동안 예상되는 크리프 허용강도는 최대파단강도의 약 60%였으며 크리프 감소계수는 1.67로 나타났다.

Keywords

References

  1. Introduction to Polymer Viscoelasticity(2nd edition) Aklonis J.J.;Macknight W.J.
  2. American Society for Testing and Materials Standard Test Methods for Evaluating the Unconfined Tension Creep Behavior of Geowynthetics ASTM D 5262
  3. Viscoelastic Properties of Pilymers(3rd edition) Ferry J.D.
  4. GRI Test Method & Standards GRI GG-4
  5. GRI Test Method & Standards GRI GS-10
  6. Designing with Geosynehetics Koerner R.M.
  7. Reinfrocement of earth slopes and embankments Mitchell, J.K.;Viller, W.C.B.
  8. Geosynehecs 98 Study on Creep-Ruqture of Polyester Tendons : Full Scale Tests Orsat, P.;Khay, M.
  9. J. of Applies Polymer Science v.25 Effect of Temperature on Creep Fracture of Polypropylene Fibers Takaku A.
  10. Geosynthetics 98 Conventional and Stepped Isothermal Methods for Characterizing Long Term Sreep Strength of Polyester Geogrid Thorton, J.S.
  11. Geosynthetics 99 The Stepped Isothermal Method for Time-Temperature Superpisition and Its Application to Creep Data on Polyster Yarn Thorton, J.S.;Allen, S.R.
  12. Geoosynthetics 99 The Relationship of Creep Curves to Rapid Lading Stress-Strain Cirves for Polyster Geogrids Thorton, J.S.;Sprague, C.J.