3. Application example

The example detailed here puts the principles of 2nd-order elastic analysis into practice. For a portal frame structure (figure 24 ), we present in succession :

• determination of the α factor _cr and whether or not a 2nd order analysis is required for the various load combinations considered;

• a global 2nd order elastic analysis taking into account P - Δ effects by amplifying lateral deformation moments (method II);

• analysis of the structure using the lump-sum method (method III, i.e. lump-sum consideration of P - Δ effects during analysis and buckling checks of columns assumed to have displaceable nodes).