Typically a four-bolt column base is usually considered to be a nominally pinned support in structural analysis. However, benefit can be taken from the stiffness of nominally pinned bases to reduce frame deflections and to reduce the effects of the deformed geometry.
Modern design codes provide several analysis options to determine the structural deflections and internal forces for dimensioning. These codes define certain usable boundaries, but between them, it is more or less the choice of the engineer which method is the most suitable to the actual design situation.
In engineering practice, for building structures, the only analysis types that are likely to be used are first-order (linear static) analysis and second-order (P-delta static) analysis.
According to Eurocode 3, if the deformed geometry significantly modifies the structural behaviour we have to take into account the influence of the deformation in the analysis. But how can we determine that our structure is sensitive for deformation or not and if it is how can we take into account during the analysis?
For a compression member, especially if it is a slender steel element, the stability check is the most crucial design situation.
In this article, we will show you how to design a steel column with axial compression to Eurocode 1993-1-1.