Buckling resistance of members: imperfection or reduction factor? - 1.

Part 1: Buckling utilization differences

The Eurocode EN 1993-1-1 offers basically two methods for the buckling verification of members:

(1) based on buckling reduction factors (buckling curves) and

(2) based on equivalent geometrical imperfections.

This article reviews how these two methods relate to each other in terms of the final member utilization. For the sake of simplicity, we consider only members subjected to pure compression, undergoing flexural-buckling. For case (1) the chapter 6.3.1 is used while for case (2) the imperfections are considered to take the shape of a buckling mode and the corresponding chapter is the 5.3.2 (11).

It is an obvious expectation that these two standard procedures should yield the same utilization for the same problem. However, this is by far not the case in general.