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?