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Effective length

How the ends of a column are supported affects how easily it buckles. The factor $K$ converts the real length into an effective buckling length $KL$ , equivalent to an imaginary pinned column with the same buckling load. A stiffer fixation gives a smaller $K$ and thus a higher buckling load.

L_{eff} = KL

effective buckling length

Symbols

$K$	effective length factor
$L$	actual column length	m

Example

A column fixed at both ends, $L = 3$ m:

$K = 0.5$ , so $L_{eff} = 1.5$ m – gives 16 times the buckling load of $K=2$ .

Pinned at both ends gives

K=1

; fixed at one end and free at the other gives

K=2

, the worst case.

Practise stress transformation and buckling for free →

← Euler buckling load

Part of Strength of Materials: Stress transformation and buckling.