Flexural-torsional buckling and its implications for steel compression member design

Abstract

Flexural-torsional and torsional buckling strength of compression members is covered for the first time in the AISC Load and Resistance Factor Design (LRFD) Specification, and, thus, must now be considered in hot-rolled steel design for buildings, in addition to overall flexural and local buckling. This new strength criterion is also included in the 1989 Allowable Stress Design (ASD) Specification. This article will attempt to provide some useful overview and practical understanding of this strength limit state. Numerical comparisons have been made to identify general trends, sensitivity to key design variables, and conclusions.