• Title/Summary/Keyword: bending stiffness reduction

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FE Analysis of the Composite Action in the Composite Beam subjected to the Hogging Moment (부모멘트를 받는 합성보의 전단합성 거동에 대한 유한요소해석)

  • Shin, Hyun-Seop
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.8
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    • pp.4048-4057
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    • 2013
  • In the composite beam subjected to the hogging moment it is very difficult to evaluate the influence of the reduction of slab stiffness due to cracks and their development on the horizontal shear behavior of shear connection. In this study, a 3D FE model is developed by which one can analyze the composite action in the composite beam subjected to the hogging moment. In this FE model, each structural member and shear connection are modeled as similar as possible to details of the composite beam. Bending behaviour, and composite action which could not be analyzed using the existing 1D or 2D FE model are investigated by the 3D model. Analysis results show that the reinforcement ratio and crack behaviour of the slab are main factors which exert a strong influence on the composite action. According to the analysis results about load-slip behavior, initial crack of slab and yielding of rebars have a influence on the slip stiffness of shear connection. The existing experimental results, that the design of partial interaction can be more efficient in designing of shear connection of the composite beams, are indirectly verified by the FE analysis.

Lap Details Using Headed Bars and Hooked Bars for Flexural Members with Different Depths (확대머리 철근과 갈고리 철근을 이용한 단차가 있는 휨부재의 겹침이음상세)

  • Lee, Kyu-Seon;Jin, Se-Hoon;Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.4
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    • pp.144-152
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    • 2016
  • This paper focuses on the experimental study for investigating the performance for lap splice of hooked or headed reinforcement in beam with different depths. In the experiment, seven specimens, with its variables as the lap length of headed or hooked bar, the existence of stirrups, etc., was manufactured. Bending test was conducted. Lap strengths by test were compared with the theoretical model based on KCI2012. The result showed that the cracks at failure mode occurred along the axial direction to a headed bar. The initial stiffness and the stiffness after initial crack were similar for all specimens. For HS series specimens without stirrups, a 25% increase in lap length was increased 11.8~18.1% maximum strengths. For HH series specimens without stirrups, a increase in lap length did not affect the maximum strengths because of the pryout failure of headed bar. For HS series specimens, the theoretical lap strengths based on KCI2012 considering the B grade lap and the reduction factor for stirrup were evaluated. They are smaller than the test strengths and can ensure the safety in terms of strength capacity. For HH series specimens, the stirrups in the lap zone are needed to prevent the pryout behaviour of headed bar.