• Title/Summary/Keyword: Virtual fixity

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The Ultimate Bearing Capacity and Estimation Method of Rigid Pile for Port Structures under Lateral Load (횡하중이 작용하는 항만구조물에서 짧은말뚝의 극한지지력 및 평가방법)

  • Kim, Byung-Il;Han, Sang-Jae;Kim, Jong-Seok;Kim, Do-Hyung
    • Journal of the Korean Geotechnical Society
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    • v.30 no.1
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    • pp.75-91
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    • 2014
  • In this study the analysis is performed for influencing factors on the behavior of rigid piles (short pile) by research papers and case study. The results indicated that the point of virtual fixity should be calculated considering the relative stiffness of soil and pile, and Chang (1937) and P-Y method estimated the similar fixity. The values of ultimate resistances of a vertical pile to a lateral load are different for laboratory and field tests in cohesive soils and its ultimate values in laboratory tests are underestimated and in field tests are under or overestimated. The estimated resistance by Hansen (1961)'s method is similar to the value of field tests. The horizontal resistances to laterally loaded pile in cohesionless soils are overestimated in laboratory tests and generally overestimated in field tests. The ultimate resistances by Zhang (2005)'s method, used to the empirical distribution of the resistance, are similar to the test results. In the paper the calculating method and distribution of the ultimate resistance in cohesive soils are proposed. The estimated value by the proposed method is closer to the test results than any other method of calculating ultimate resistance of the piles embedded into cohesive soils.

Theoretical Stiffness of Cracked Reinforced Concrete Elements (철근콘크리트 부재의 균열 후 강성 이론)

  • 김장훈
    • Journal of the Korea Concrete Institute
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    • v.11 no.5
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    • pp.79-88
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    • 1999
  • The purpose of this paper is to develop a mathematical expression for computing crack angles based on reinforcement volumes in the longitudinal and transverse directions, member end-fixity and length-to-width aspect ratio. For this a reinforced concrete beam-column element is assumed to possess a series of potential crack planes represented by a number of differential truss elements. Depending on the boundary condition, a constant angle truss or a variable angle truss is employed to model the cracked structural concrete member. The truss models are then analyzed using the virtual work method of analysis to relate forces and deformations. Rigorous and simplified solution schemes are presented. An equation to estimate the theoretical crack angle is derived by considering the energy minimization on the virtual work done over both the shear and flexural components the energy minimization on the virtual work done over both the shear and flexural components of truss models. The crack angle in this study is defined as the steepest one among fan-shaped angles measured from the longitudinal axis of the member to the diagonal crack. The theoretical crack angle predictions are validated against experimentally observed crack angle reported by previous researchers in the literature. Good agreement between theory and experiment is obtained.