ABSTRACT
In this paper a novel analytical model is developed for determining the load capacity for the lateral-torsion buckling of statically indeterminate zed purlins (a single span beam with one or two ends fixed), with partial lateral restraint from metal sheeting, when subjected to a uniformly distributed uplift load. The model takes account the influence of the “softening” of the section stiffness due to local buckling and/or local material yielding. The analytical model developed in this paper, together with the numerically or experimentally obtained curves describing the local stiffness softening, can be used to determine the critical load for lateral-torsion buckling of the statically indeterminate purlin.
