Summary

• Columns are commonly found in many types of building.
• Columns carry load principally by axial compression.
• The strength of stocky columns is related to material strength.
• The strength of slender columns is limited by buckling.
• In practice steel columns have to allow for both buckling and material failure, and for interaction between the two.
• The resistance of a cross-section to buckling is represented by its radius of gyration.
• End conditions influence buckling behaviour and are accounted for by using an effective length.
• In practice columns are subject to a combination of compression and bending.
• Because buckling resistance and actual stress are both related to the size of the cross-section, iterative design procedures must be used.