BUCKLING OF RESTRAINED COLUMNS WITH SHEAR DEFORMATION AND AXIAL SHORTENING

There are two well-known approaches proposed for incorporating shear deformation in the analysis of column buckling. Engesser's approach assumes that the shear component acts perpendicularly to the total slope while Haringx's approach assumes that it acts perpendicularly to the bending slope. It appears that discussions are still going on as to which of the approaches is more accurate. It is doubtful if the problem can be resolved through mechanics, as Reissner had pointed out that the approaches depend on the form of the assumed, one-dimensional, stress-strain relations. This paper will use Engesser's approach for the shear-flexural buckling analysis of continuously restrained columns. The effect of axial shortening is also considered. A derivation is presented for the total potential energy functional, which forms the basis of the finite element method for solution. A parametric study is carried out to investigate sensitivity to various design parameters.