Elastic local buckling coefficients of I-shaped beams considering flange

Elastic local buckling coefficients of I-shaped beams considering flange–web interaction

Lee, Jeonghwa / Kang, Young Jong

Highlights • Elastic local buckling behavior and strength of flanges and webs in I-shape structural sections was investigated based on finite element analysis. • Effects of flange and web interaction on local buckling of flanges and webs was evaluated in terms of ratio of flange-web slenderness and height-to-width ratio. • Improved design equations of local buckling coefficients in flange and web bend buckling were proposed. • The proposed design equations shows a good correlation with FEA results when compared with equations in literature.

Abstract Since using high–strength and high–performance steels has become a more common structural design practice in building and bridge construction, there is an increased potential for designing extremely thin-walled I-shaped beam members to enhance the efficiency of the steel beam design. For a more accurate design approach for these thin-walled I-beam members, particularly when they are near noncompact limits, it is necessary to explore more rational methods for determining the elastic local buckling strength of I-beams. This study aimed to investigate the local buckling behavior and strength of I-shape structural sections by considering flange-web interactions through three-dimensional finite element analysis. The goal was to provide a more reasonable estimation of local buckling strength under uniform bending. To evaluate the local buckling behavior of flange and web panels and explain it reasonably, this study adopted the ratio of flange-web slenderness ( $λ_{f} / λ_{w}$ ) and height-to-width ratio ( $H / b_{f}$ ) of I-shaped beams which can affect buckling mode shapes and local buckling strength of I-shaped beams induced by flange local and web bend bucklings. Finally, this study presented design equations for both flange local and web-bend buckling coefficients considering $λ_{f} / λ_{w}$ and $H / b_{f} .$ It was expected that the presented local buckling coefficients ( $k_{f}$ ) for flanges and webs could lead to a more reasonable design, as compared to the existing AISC design provisions.