Second order P-Delta Solver in Windas is meant to take into account geometrical imperfections on each element as well as imperfections on frame global analysis.
Ref Engineering Report P2019074:
According to EN 1993-1-1 Clause 5.3.1, appropriate allowances should be incorporated in the structural analysis to cover the effects of imperfections, including residual stresses and geometrical imperfections, such as lack of verticality, lack of straightness, lack of flatness, and lack of fit present in joints of an unloaded structure. Therefore, the following imperfections have been taken into account in the analysis when obtaining end member forces for member design checks:
- Global imperfections – by considering the additional loads due to P-Δ effects (i.e. effect of loads acting on the displaced location of joints or nodes in a structure).
- Local Imperfections for individual member – by considering the additional loads due to P-δ effects (i.e. effect of loads acting on the deflected shape of a member between joints or nodes)