We consider elastic buckling of an inextensible beam confined to the p
lane and subject to fixed end displacements, in the presence of rigid,
frictionless side-walls which constrain overall lateral displacements
. We formulate the geometrically nonlinear (Euler) problem, derive som
e analytical results for special cases, and develop a numerical shooti
ng scheme for solution. We compare these theoretical and numerical res
ults with experiments on slender steel beams. In contrast to the simpl
e behavior of the unconstrained problem, we find a rich bifurcation st
ructure, with multiple branches and concomitant hysteresis in the over
all load-displacement curves.