An annular plate ringbeam at the transition junction of a uniformly-su
pported steel silo or tank is subject to a large circumferential compr
essive force that is derived from the radial component of the meridion
al tension in the conical hopper. Under this compressive force, the ri
ngbeam may fail in one Of Several possible modes, including out-of-pla
ne buckling, This paper presents an investigation into the effects of
various factors on the plastic out-of-plane buckling behavior and stre
ngth of this ringbeam, leading to the eventual development of a simple
plastic buckling approximation for design use. The application of the
proposed method is demonstrated through an example.