Behaviour of Single Angle Steel Beams (No. R884)

A single angle steel beam is commonly loaded eccentrically in a plane inclined to the principal planes (Fig. 1), so that the beam undergoes primary bending and shear about both principal axes, torsion, and bearing at the supports. The strengths of such beams are affected by local buckling effects on their section resistances, and by lateral buckling effects and torsion on the interaction between the major and minor axis moments during biaxial bending. This paper summarises the behaviour of single angle steel beams investigated in a series of recent papers. For these papers, the general case of unrestrained biaxial bending and torsion was simplified successively (Fig, 2) into restrained biaxial bending, lateral buckling, unrestrained biaxial bending, buckling and torsion, and biaxial bending and torsion. The paper concludes that despite the apparent simplicity of single angle beams, their behaviour is often complex and their strengths difficult to predict. The papers summarised provide a design method which is rational, consistent and economical