ABSTRACT
This chapter discusses the influences of the elastic buckling load and the squash load on the behaviour of concentrically loaded compression members and related to their design according to AS4100. The analysis of a perfectly straight elastic compression member applies only to a material whose stress-strain relationship remains linear. The presence of residual stresses in an intermediate length steel compression member may cause a significant reduction in its buckling strength. The shrinking of the late-cooling regions of the member induces residual compressive stresses in the early-cooling regions, and these are balanced by equilibrating tensile stresses in the late-cooling regions. The application of the method of design by buckling analysis to rigid-jointed frames which only have joint loads is a simple extrapolation of design method for simply supported compression members. Real compression members may be analysed using a model in which initial crookedness and load eccentricity are specified. The tangent modulus theory of buckling is only valid for elastic materials.
