Combined Load Stability Criterion for Wood Beam-Columns

An analysis of elastic buckling in beam‐columns was undertaken to develop a general interaction equation for use in timber design. The derivation of a general buckling criterion and the determination of moment modification factors following the method of Southwell (1922) are presented. Biaxial bending, axial compression, and water ponding on flat roofs are all considered. Simple support is assumed, but results may be applicable to other support cases. The results are of interest to code developers and to designers of space frames, towers, and trusses, where biaxial bending and axial compression are combined, or whenever axial compression and water ponding may be combined.