A simply supported compression member consists of a standard structural steel cross-section. Because of the lower bending stiffness in one plane compared to the other for most standard cross-sections, such a member would tend to fail by buckling in the weaker direction. One strategy of raising the buckling load is to constrain the lateral motion at the center of the member-the beam then has a buckling load that corresponds to a member that is half as long. Say that the lateral motion is constrained only in the weaker direction. Consider how much this strategy raises the buckling load for two cross-sections:
(a) a wide-flange section W6 x 25 and
(b) a standard channel section C9 x 15. For each section, compute the ratio of the constrained buckling load to the unconstrained buckling load. Also, for each section, specify whether the plane of buckling changes when the constraint is added. (See Appendix E.)
