Steel Buildings in Europe

Part 3: Actions 3 - 6 The choice between  1,1 Q k,1 or  2,1 Q k,1 should be related to the relevant accidental design situation. Guidance is given in EN 1990 or in the National Annex to EN 1990. 3.3 SLS combinations 3.3.1 Serviceability Limit State To verify a serviceability limit state, it shall be ensured that: E d ≤ C d where: E d is the design value of the effects of actions specified in the serviceability criterion, C d is the limiting design value of the relevant serviceability criterion. 3.3.2 Characteristic combination The characteristic combination is normally used for irreversible limit states. Permanent actions Leading variable action Accompanying variable actions E d =   1 k, j j G + k,1 Q +   1 k,i 0,i i Q  For example, with snow as the leading variable action: E d = G + S + 0,6 W E d = G + S + 0,7 Q ( Q being the imposed load in an office building) 3.3.3 Frequent combination The frequent combination is normally used for reversible limit states. Permanent actions Leading variable action Accompanying variable actions E d =   1 k, j j G + 1,1 k,1 Q  +   1 k,i 2,i i Q  For example, with snow as the leading variable action: E d = G + 0,2 S (  2 = 0 for the wind action) E d = G + 0,2 S + 0,3 Q ( Q being the imposed load in an office building)