Buckling lengths

1. INTRODUCTION

For the determination of the elastic Euler critical buckling load

it is assumed (as per Concepts of Stable and Unstable Elastic Equilibrium lecture) that both ends of the column are pinned (see Figure 1). Practical end connections on real columns, however, will often not behave in this manner and this will, therefore, significantly affect the buckling load. Two aspects of the end condition must be considered:

• the rotation restraints which can vary between 0 and ∞ (i.e. a hinge without friction or fully restrained)
• the translational restraints (sway or no sway)

The usual design approach consists of reducing the practical case under consideration to an equivalent pin-ended case by means of an effective length factor K.