Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Nonlinear Three-dimensional Analysis of Piled Piers Considering Coupled Cap Rigidities

교량 말뚝기초의 캡강성을 고려한 비선형 3차원 해석

  • 원진오 (연세대학교 공과대학 토목공학과) ;
  • 정상섬 (연세대학교 공과대학 토목공학과)
  • Published : 2005.08.01
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Abstract

A coupled three-dimensional pile group analysis method was developed by considering complex behavior of sub-structures (pile-soil-cap) which included soil nonlinearity and the behavior of super-structure (pier). As an intermediate analysis method between FBPier 3.0 and Group 0.0, it took advantages of each method. Among the components of a pile group, individual piles were modeled with stiffness matrices of pile heads and soils with nonlinear load-transfer curves (t-z, q-z and p-y curves). A pile cap was modeled with modified four-node flat shell elements and a pier with three-dimensional beam element, so that a unified analysis could be possible. A nonlinear analysis method was proposed in this study with a mixed incremental and iteration techniques. The proposed method for a pile group subjected to axial and lateral loads was compared with othe. analytical methods (i.e., Group 6.0 and FBPier 3.0). It was found that the proposed method could predict the complex behavior of a pile group well, even though piles were modelled simply in this study by using pile head stiffness matrices which were different from the method introduced in FBPier 3.0.

. 본 연구에서는 지반의 비선형을 고려한 하부구조(말뚝지반말뚝캡)의 복잡한 거동과 상부 피어구조와 연계된 상$\cdot$하부 일체화 해석을 수행할 수 있는 3차원 해석기법을 개발하였다. FBPier 3.0과 Croup 6.0의 중간단계에 해당하는 해석기법으로 각 해석기법의 장점을 취하고 단점을 보완하였다. 군말뚝기초 중 말뚝은 말뚝두부 강성행렬을 이용하여 모델링하였으며, 지반은 비선형 하중전이곡선(t-z, q-z, p-y곡선)으로 나타내었다. 말뚝캡은 6개의 자유도를 갖는 개선된 4절점 평면쉘(Flat shell)요소루 교각(피어)은 3차원 보(Beam)요소로 모델링 하여 상$\cdot$하부 일체해석이 가능하게 하였다. 말뚝두부 강성행렬의 하중크기에 따른 비선형성을 고려하기 위하여 점증하중-할선계수법을 제안하였다. 기존의 비선형 해석기법과의 비교$\cdot$분석 결과, 본 해석기법이 말뚝을 FBPier 5.0과 달리 말뚝두부 강성행렬을 이용하여 모델링 하였어도 말뚝두부 및 교각 상단에서의 변위를 비교적 정확히 산정 가능하였다.

Keywords

References

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