A finite element for the elastic stability analysis of frameworks.
The elastic and geometric stiffness matrices are developed from 1st principles for a beam-column element which is to be used in the linear elastic stability analysis of frameworks. The element formulation is extensively tested against classical and experimental results for beams, columns, and frames. A practical application of the element is demonstrated by using it to investigate the lateral stability of a number of rigid jointed trusses. The bracing requirements of these trusses are compared with the requirements of the bracing to pinned columns, which are the same size as the compression chord of the trusses, and have either a constant or stepwise parabolic distribution of axial load. It is found for most bracing cases, that the critical load and the bracing requirements for a truss, can be closely estimated from an analysis of a column with a "parabolic" axial load distribution.