The design value (F_{d}) of an action [EC0, 6.3.] is equal to the product of the characteristic value F_{k} times the factor γ_{f} (F_{d}=γ_{f}·F_{k}). The values of γ_{g} (multiplying the permanent values G_{k}) and γ_{q} (multiplying the variable values Q_{k}) are stated on the following table [EC0, table A1.2(B)].   Unfavourable γ_{g}_{,}_{sup}   Unfavourable γ_{q}_{,}_{sup}  Favourable γ_{q}_{,}_{sup}     
In certain structures, taking account of the uncertainties in modelling effects of actions or in modelling the actions, a second partial factor γ _{Sd} is involved in the calculation affecting the actions safety factor γ_{F}=γ_{Sd}·γ_{f} (γ_{G} =γ_{Sd}·γ_{g}, γ_{Q}=γ_{Sd}·γ_{q}). Although the value of γ_{Sd} depends on the designer, in such cases, its value usually varies between 1.05 and 1.15. Vibrations produced by earthquakes cause seismic accelerations to the structure. The structure's seismic response depends on the seismic Zone Z of the building, the Type of Soil, the Factor of Importance γ_{I}, the Viscous Damping ξ, the Behaviour Factor q and of course the magnitude and distribution of stiffness EI and the mass M of the structure. Calculations, simple or extremely complicated (§6.3), result, for every seismic combination i, at each position of the structure j with mass M_{j}, to the maximum seismic design acceleration a_{i,j,}. The design seismic force for the combination i at position j is equal to F_{i,j}=a _{i,j}·M_{j}._{}Forces F_{i,j} represent the Seismic Actions.
