Elastic flexural local buckling of Litzka castellated beams: Explicit equations and FE parametric study

• Published in: Engineering structures Vol. 186; pp. 436 - 445
• Main Authors: de Oliveira, Julia Pithan, Cardoso, Daniel Carlos Taissum, Sotelino, Elisa Dominguez
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-05-2019; Elsevier BV
• Subjects: Beam theory (structures); Buckling; Castellated beams; Compression; Eigenvalues; Elastic buckling; Finite element method; High strength steels; Litzka beams; Local buckling; Mathematical analysis; Parametric statistics; Steel; Stiffness; Stress; Stresses; Webs; Castellated beams; Local buckling; Litzka beams
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2019.02.034

•Explicit equations for ‘tee’ buckling are developed using energy method.•Influence of transverse bending of web is considered.•Parametric analysis is carried out using FEM for Litzka-type beams.•Influence of stress gradient in the ‘tee’ buckling is studied using GBT.•It is shown that this buckling mode be relevant for high-strength steel.
This work presents the development of explicit equations for the prediction of elastic local buckling critical stress of castellated beams subjected to pure bending, considering the interaction between flange and web. Eigenvalue analyses are carried out for Litzka-type beams using Finite Element Method (FEM) to gather information on the buckling modes and critical stresses for combinations of usual flange-to-web width and thickness ratios. The representative compression ‘tee’ is analyzed using the Generalized Beam Theory (GBT) to study the influence of stress gradient and member length in the critical stress. The influences of flange torsional stiffness and web transverse bending in the ‘tee’ behavior are studied and an energy method is adopted to derive the prediction equations. It is shown that the proposed approach leads to a good agreement with the FEM results, with an average difference of 0.955 ± 0.063, whereas current guidelines may significantly over or underestimate actual critical stresses for low flange-to-web width ratios. It is finally shown that this buckling mode may become relevant for castellated beams using high-strength steel.