A NUMERICAL INVESTIGATION ON THE INTERACTION BETWEEN GLOBAL AND LOCAL BUCKLING MODES IN CASTELLATED BEAMS

Resumo

The present work aims to investigate the interaction between lateral torsional buckling and
compression ‘tee’ local buckling in castellated beams. Finite element method (FEM) is used to perform
a parametric analysis for Litzka-beams subject to pure bending moment and considering combinations
of flange-to-web width and thickness ratios and unbraced lengths. To account for the possibility of
different yield strengths, non-dimensional local and global slenderness are used to assess the behavior
in a comprehensive manner. The responses for beams having different combinations of slendernesses
are compared and the relative strengths are discussed. The FEM ultimate bending moments are
compared to those calculated according to the current design recommendations for castellated beams,
showing that these may either over or underpredict actual capacities. Finally, a direct strength method
approach is tested for the prediction of the nominal bending strength.