Cubic beam elements in practical analysis and design of steel frames

This paper discusses various issues in the use of cubic beam elements for c omputer structural analysis/design of steel frames. It is pointed out that the concern expressed in recent literature regarding the number of cubic el ements required to model a steel member is not justified, and that the inac curacy of one cubic element in Euler buckling analysis of a simply supporte d column is largely irrelevant to the second-order elastic analysis/design or advanced analysis of steel frames. The sources of inaccuracy of the cubi c element are elucidated. It is also explained that the plastic-zone analys is method is not so inefficient as was previously believed. The spatial cub ic element is shown to be capable of accurately accounting for the coupling between axial, flexural and torsional deformation modes. It is concluded t hat for the purposes of second-order elastic analysis/design and advanced a nalysis of 2D and 3D steel frames, the well-documented cubic element is a v ersatile and efficient choice. (C) 2001 Elsevier Science Ltd. All rights re served.