EHFs are a set of notional lateral loads used to mimic the effect of construction global imperfections (like out of plumb). The Eurocode requires they are applied to all combinations. (Lateral wind combinations therefore should also have EHFs applied).

EHFs are automatically derived from the factored loadcases within the current combination. They are applied in the analysis as a horizontal force at each beam column intersection as a specified percentage of the vertical load in the column at the column/beam intersection.

Settings that control the EHF percentage can be adjusted from Home > Model Settings > EHF (Global Imperfections).

From here, the structure height and numbers of columns in X and Y allow φ, the % needed to calculate the EHF to be determined. (The default settings conservatively result in 0.5% EHF in both directions). A facility is also provided to override this value if required.

Four loadcases (EHF_Dir1+, EHF_Dir1-, EHF_Dir2+, EHF_Dir2-) are then made available for applying EHFs in each of the building directions when creating load combinations.

Once you have created EHF combinations and performed the analysis, you can view the magnitude of the notional loads from the project workspace. You can also display their magnitude and direction graphically in a results view.