Buckling, Postbuckling, Strength, and DSM Design of Cold-Formed Steel Continuous Lipped Channel Beams

Abstract

The work reported in this paper is part of an ongoing numerical investigation aimed at (1) assessing the buckling, postbuckling, strength, and collapse behavior of cold-formed steel continuous beams and simple frames and (2) developing an efficient methodology, based on the direct strength method (DSM) approach, to design such structural systems. The results available at this stage concern two- and three-span lipped channel beams subjected to nonuniform bending, and they include the assessment of how accurately the beam ultimate strengths can be predicted by the current DSM design curves. The numerical results presented and discussed are obtained through analyses based on generalized beam theory (elastic buckling analyses) and shell finite-element models (all the remaining analyses). Ultimate strength values yielded by geometrically and materially nonlinear shell finite-element analyses are compared with estimates provided by the DSM equations, and on the basis of this comparison, it is possible to identify some features that must be included in a DSM approach applicable to continuous cold-formed steel beams.