• Title/Summary/Keyword: unsymmetric axis

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A Study on Optimum Section of New Type Steel-Concrete Composite Beam (신형상 층고절감형 합성보의 최적단면 도출에 관한 연구)

  • Yoon, Myung-Ho;Lee, Yoon-Hee
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.2 no.3
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    • pp.30-35
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    • 2011
  • This study investigates the optimum section properties of newly developed steel-concrete composite beam. For that purpose we developed computer program calculating section properties. The suggested new beam section highly contribute to save inter-story height and reduce construction duration and cost compared with conventional steel works such as H-beam and column + RC slab system. But the section shape have different section modulus with upper and lower fiber because of the unsymmetric cross section. Therefore the parametric study on thickness-ratio of top and bottom flange plate is needed. In this paper the change of neutral axis and section modulus for thickness-ratio of up and down flage plate is analysed and discussed.

Free Vibration Analysis of a 3-dimensional Cable-Stayed Bridge with the Unsymmetric Girder Cross-section (비대칭단면 주형을 갖는 3차원 사장교의 고유진동해석)

  • Kim, Chul Young;Chang, Sung Pil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.11 no.2
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    • pp.15-26
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    • 1991
  • The lateral forces such as the earthquake and wind my cause the torsion to be coupled with the lateral bending in the gider, the cross-section of wich has only one axis of symmetry. This induces additional stresses especially in cables arranged in double-planes. Since this effect cannot be considered by using the conventional frame elements, the stiffness and the mass matrices of the geometrically nonlinear thin-walled frame element are developed in this study to model the girder. The equivalent modulus of elasticity proposed by Ernst is used for the cable elements. Verification of the present theory is made through a numerical example. Then, the free vibration of a three dimensional cable-stayed bridge is analyzed to study the coupled flexural-torsional behavior.

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Free Vibration Analysis of Thin-walled Curved Beams with Unsymmetric Cross-section (비대칭 단면을 갖는 박벽 곡선보의 자유진동 해석)

  • 김문영
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.1
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    • pp.41-54
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    • 1999
  • For free vibration of non-symmetric thin-walled circular arches including restrained warping effect, the elastic strain and kinetic energy is derived by introducing displacement fields of circular arches in which all displacement parameters are defined at the centroid axis. The cubic Hermitian polynomials are utilized as shape functions for development of the curved thin-walled beam element having eight degrees of freedom. Analytical solution for in-plane free vibration behaviors of simply supported thin-walled curved beams with monosymmetric cross-sections is newly derived. Also, a finite element formulation using two noded curved beams element is presented by evaluating elastic stiffness and mass matrices. In order to illustrate the accuracy and practical usefulness of this study, analytical and numerical solutions for free vibration of circular arches are presented and compared with solutions analyzed by the straight beam element and the ABAQUS's shell element.

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