Effective length
Strong enough and still falls over
A column can fail at a fraction of the load its material could carry, by going sideways. Buckling is a failure of stability rather than of strength, and it is decided by geometry.
The ends decide the length that matters
Four columns of identical height and section, buckling at loads sixteen times apart. Nothing differs but what is holding the two ends.
The load that makes itself worse
A structure that has leaned carries its weight off the axis, which makes it lean further. The amplification is one over one minus the load ratio, and it runs away long before the buckling load.
The beam that fails sideways
A deep narrow beam bending in its strong plane can, at a moment well below its capacity, swing out of that plane and twist. The failure has nothing to do with how much it can carry and everything to do with what is holding it.
The brace that need not be strong
A brace holding a column at mid-height carries almost no force. What it has to be is stiff — and the stiffness required is exact, large, and reached at a knee past which more buys nothing at all.
Named alongside it
The objects these essays reach for when they reach for this one.
ImperfectionBracingBuckled mode shapeCritical loadLateral restraintSlendernessAmplification factorCompression flangeCritical momentEccentricityEigenvalueEnd restraint