Global sway imperfections EC3

[JoelNC]

Hi,

I have some doubts on when to apply global sway imperfections on steel frames according to EN1993-1-1 5.3.2. According to 5.3.2(4), we can disregard the sway imperfections if the total horizontal load is more than 15% of the total vertical load in a given ULS combination. Is this the main criteria used to define if we need to apply global imperfections or not?

Can anyone give me advice on when to consider global sway imperfections properly?

Thanks

 

[HTURKAK]

The sway imperfections are second order effects applied to Wall bracings and columns. In steel structures, there can be imperfections, such as: residual stresses, eccentricities of load, lack of verticality , eccentricities in joints..

The sway imperfections may be included in analysis by applying equivalent horizontal forces and may be neglected if


HEd ≥ 0.15 VEd

There are some worrked examples at this free document ;

https://www.steelconstruction.info/images/c/c5/SCI_P397.pdf

Does this reply answer to your question ?

If not, i will suggest you to look the book ( DESIGN OF STEEL STRUCTURES Eurocode 3: Part 1-1 – General rules and rules for buildings by; Luís Simões da Silva ,Rui Simões..)

 

[JoelNC]

Thanks HUTRKAK. The worked examples also help a lot to clarify my question. My main conclusion is that we should always consider the sway imperfections (by applying EHF for example) and they may be neglected only if HEd ≥ 0.15 VEd, as you mentioned.