DIRECT STRENGTH PREDICTION OF LIPPED CHANNEL COLUMNS EXPERIENCING LOCAL-PLATE/DISTORTIONAL INTERACTION

This paper reports an ongoing investigation intended to assess the performance of the Direct Strength Method (DSM) to estimate the ultimate strength of lipped channel columns affected by local-plate/distortional mode interaction.First, the DSM approaches to safety check columns against local-plate and distortional failures are briefly reviewed, with special attention devoted to a recently proposed extension that takes into account the above buckling mode interaction.Next, one presents and discusses the results of a parametric study, carried out by means of the code ABAQUS and involving the evaluation of the "exact" ultimate loads of 63 lipped channel columns with various geometries, all exhibiting local-plate/distortional interaction.Then, these ultimate strength data are compared with the estimates provided by the available DSM formulae and, on the basis of this comparison, one identifies several features that a DSM approach successfully accounting for local-plate/distortional interaction must incorporate.