• Title/Summary/Keyword: moment gradient correction factor

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A Study on the Evaluation of elastic buckling strength of Singly Symmetric I-Beams (일축대칭 I형보의 탄성좌굴강도 산정에 관한 연구)

  • Ku, So-Yeun;Ryu, Hyo-Jin;Lim, Nam-Hyoung;Lee, Jin-Ok
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.79-82
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    • 2008
  • The elastic critical moment of I-beams subjected to moment is directly affected by the following factors; loading type; loading position with respect to the mid-height of the cross section; end restraint conditions. Most design specifications usually provide buckling solutions derived for uniform moment loading condition and account for variable moment along the unbraced length with a moment gradient correction factor applied to these solutions. In order for the method in the SSRC Guide to be applicable for singly symmetric I-beams, improved moment gradient correction factors were proposed in this study. Finite element buckling analyses of singly symmetric I-beams subjected to transverse loading applied at different heights with respect to the mid-height of the cross section were conducted. Transverse loads consisting of a mid-span point load and a uniformly distributed load were considered in the investigation.

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Modified Moment Gradient Correction Factor of Nonprismatic Beams (변단면보의 개선된 모멘트 구배 수정계수)

  • Park, Jong Sup
    • Journal of Korean Society of Steel Construction
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    • v.18 no.2
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    • pp.191-201
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    • 2006
  • New design equations for calculating the lateral-torsional buck ling moment resistances of stepped I-section beams with/without continuous lateral top-flange bracing subjected to a point load, a series of point loads, and a uniformly distributed load, are suggested based on the results of elastic finite-element analyses. The new equations presented in this study are compared with the current moment gradient modifiers presented by other researchers and specifications. Although the study paper presents mainly stepped-beam cases subjected to a point load and a uniformly distributed load. The proposed equations include the length-to-height ratio effects for stepped beams with continuous lateral top-flange bracing. The new moment gradient correction factors could be easily used to calculate the lateral-torsional buckling moment resistance of stepped I-beams.

Lateral buckling formula of stepped beams with length-to-height ratio factor

  • Park, Jong Sup
    • Structural Engineering and Mechanics
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    • v.18 no.6
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    • pp.745-757
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    • 2004
  • Lateral-torsional buckling moment resistances of I-shaped stepped beams with continuous lateral top-flange bracing under a single point load on the top flange and negative end moments were investigated. Stepped beam factors and a moment gradient correction factor suggested by Park et al. (2003, 2004) were used to develop new lateral buckling formula for beam designs. From the investigation of finite element analysis (FEA), new lateral buckling formula of beams with singly or doubly stepped member changes and with continuous lateral top-flange bracing subjected to a single point load on top flange and end moments were developed. The new design equation includes the length-to-height ratio factor to account for the increase of lateral-torsional buckling moment resistance as the increase of length-to-height ratio of stepped beams. The calculation examples for obtaining lateral-torsional buckling moment resistance using the new design equation indicate that engineers should easily determine the buckling capacity of the stepped beams.

Elastic Lateral Buckling Strength of Singly Stepped Beams with Load Height Effect (하중고 효과를 고려한 일단 변단면보의 탄성좌굴강도식 개발)

  • Park Jong-Sup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.1
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    • pp.63-69
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    • 2006
  • New design equations for calculating the lateral-torsional buckling moment resistances of singly stepped I-section beams subjected to general loading on the top flange are suggested based on the investigations of elastic finite-element analyses. The new equations presented in this study are compared with current moment gradient modifiers presented by other researchers and specifications. The study considered almost loading cases on buildings and bridges. The proposed equations should be easily used to calculate the lateral-torsional buckling moment resistance of stepped I-beams.

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Lateral-Torsional Buckling Strength of I-girder with Corrugated Steel Webs under Linear Moment Gradient (선형 모멘트 구배가 작용하는 파형강판 I-거더의횡-비틂 좌굴 강도)

  • Moon, Jiho;Lim, Nam-Hyoung;Lee, Hak-Eun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.3A
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    • pp.149-160
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    • 2012
  • Corrugated steel plates have several advantages such as high resistance for shear without stiffeners, minimization of welding process, and high fatigue resistance. To take advantage of these benefits, several researchers have attempted to use corrugated steel plate as a web of I-girders. The lateral-torsional buckling is the major design aspect of such I-girders. However, lateral-torsional buckling of the I-girder with corrugated steel webs still needs to be investigated especially for a real loading condition such as non-uniform bending. This paper investigated the lateral-torsional buckling strength of the I-girder with corrugated steel webs under linear moment gradient by using finite element analysis. From the results, it was found that the buckling behavior of the I-girder with corrugated steel webs differed depending on the number of periods of the corrugation. Also, a simple equation for the moment gradient correction factor of the I-girder with corrugated steel webs was suggested. The inelastic lateral-torsional buckling strength of the I-girder with corrugated steel webs was then discussed based on current design equations for ordinary I-girders and the results of finite element analysis.

Elastic Buckling of Monosymmetric I-beams considering Load Height Effects (하중고 효과를 고려한 일축대칭 I형보의 탄성 좌굴)

  • Ryu, Hyo Jin;Park, Gyung Hyeon;Kim, Jung Hun;Lim, Nam Hyoung
    • Journal of Korean Society of Steel Construction
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    • v.20 no.1
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    • pp.175-181
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    • 2008
  • Finite element buckling analyses of the monosymmetric I-beams subjected to t ransverse loading applied at different heights with respect to the mid-height of the cross section were conducted. Transverse loads consisting of a mid-span point load and a uniformly distributed load were considered in the investigation. The method suggested in the SRC Guide was compared with the finite element method (FEM) results. This paper presents a more accurate moment gradient correction factor for monosymetric I-beams considering the load height effect. The applicability of this new design method is limited to monosymmetric I-beams in which the degree of monosymetry, ${\rho}$, is from 0.1 to 0.9.