Steel Buildings in Europe

Part 3: Actions 3 - 7 3.3.4 Quasi-permanent combination The quasi-permanent combination is normally used for long-term effects and the appearance of the structure. Permanent actions Variable actions E d =   1 k, j j G +   1 k,i 2,i i Q  For example: E d = G + 0,3 Q ( Q being the imposed load in an office building) 3.3.5 Floor vibration In multi-storey buildings, floor vibration is sometimes a serviceability limit state that is critical in the design. There is no specific rule in the Eurocodes. Limits may be given in the National Annexes. A simple rule is generally to require the frequency to be higher than a minimum value (3 or 5 Hz for example); the frequency being assessed from the total permanent loads and a fraction of the imposed loads I (for example: G + 0,2 I ). This approach is often too conservative and more advanced methods are available, see the Design guide for floor vibrations [8] . additional information is given in Multi-storey steel buildings. Part 4: Detailed design [9] .