topic Re: Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach in Robot Structural Analysis Forum

Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach

Anonymous — Thu, 30 Apr 2015 15:28:20 GMT

Hi,

I`m scratching my head for some time about how to implement the "Equivalent Horizontal Forces" (EHF) into the model when designing to Eurocode.

These forces should be applied in all principal directions of the structuire and are to be based on the factored vertical loads. These forces should be part of each combination considered.

Introducing individual load cases for EHF seems too laborious job - for rectangular building it would typically mean 4 EHF cases for each vertical case (i.e. one for each direction - say +X, -X, +Y, -Y).

Can Autodesk please advise on how to approach the modeling or provide any example of a model (it can be very simple one)?

I am quite surprised that such fundamental aspect of Eurocode requirement hasn`t been discussed yet on this forum. Aplogogiies if it has, but was striggling to find it.

I noticed that many other pieces of analysis and design software cover this aspect by very simple automatized process (prety much by ticking the box when creating combinations).

Many thanks for help.

Best Regards

Tomas Bilek

Re: Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach

Artur.Kosakowski — Thu, 30 Apr 2015 15:47:26 GMT

Loads > special loads > notional loads

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

Re: Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach

Anonymous — Thu, 30 Apr 2015 17:11:33 GMT

Thank you for indication of where to find the vertical to horizontal force conversion tool. Could you please advise on the workflow or methodology for complying with the Eurocode using this tool bearing in mind the combination factors?

From what I see it apears that I need to generate the notional cases (+X, -X, +Y, -Y) for each individual vertical case to be able to assign the approriate partial (γ) and combination (ψ) factors when creating individual load combinations. The problem seems to be however that Robot doesn`t allow me to create more than one "Notional loads" (that`s how it names it automatically) for each of the four principal direction. If that is the case then I can`t see how to generate the appropriate loads for the design.

Additionally, is there any option how to deal with non-ortogonal buildings? For example if I need to apply the EHF at 45 degrees when looking at plan? This tools sees to be working only for 0,90,180 and 270 degrees.

Many Thanks

Tomas

Re: Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach

Anonymous — Wed, 06 May 2015 08:37:11 GMT

I have recently spent a lot of time trying to figure this out, but no joy! Very frustrating considering this is supposed to be a trivial task (and one of the reasons for using computers).

Can someone please drop any comments on how he/she deals with such fundamental and pretty much mandatory think when designing to Eurocodes?

Or is it just not possible? It would be helpful if Autodesk said what is the case as one doens`t have to waste more time.

Tomas

Re: Equivalent Horizontal Forces (EHF) to Eurocode - Modelling Approach

Artur.Kosakowski — Wed, 06 May 2015 09:55:59 GMT

Why don't you just write a name of the case you want to create and press the Add button after selection of the load case to convert?