FEA structures and UK Building Regs?

[mbga9pgf]

For complex structures (we are talking about modern family homes with complex steel and wood structure)how do I go about using FEA to prove design limits are not broached? I have a number of structural engineering books and all show how to design simple structures to UK building regs, using British Standards, and refer to FEA being used to design complex structures, but none tell you:

Whether seperate safety factors apply (cant Imagine they would??)

How the planning authority can check the validity of the FEA model (accuracies vary, depending on modelling method, number of nodes etc) so how do they know if the FEA model is valid?

Are there any British Standards which cover this? I can't seem to find any?

Thanks in advance,

Mbga

 

[csd72]

I have never heard of FEA being used to design family homes no matter how complicated.

It is much quicker to design these things by hand.

I doubt that the building department will know what to do with the FEA results so you may have a difficult time getting it passed for building regs.

FEA is just another method of analysis so all relevant code clauses still apply.

csd

 

[mbga9pgf]

was looking to design a complex structure, using a combination of aerospace techniques and traditional materials... not to sure British standards cover something like this....

http://www.ccanw.co.uk/images/Korkeasaari-Lookout-Tower.jpg

Guessing some blunty beaurocrat wont want anything as innovative as that built in the UK though... far too interesting. :-(

 

[valleyboy]

I'm a blunty beaurocrat working for a Local Authority in the UK, and get involved with checking Building Regulation Applications for compliance with Part A.

I can only speak for my Authority, but we do not have FEA capability in the analysis packages that we have in the office - but I agree with csd72 that the element design will need to be carried out in accordance with the relevant code after analysis with FEA.

In the case of steel and timber structures, this will be BS 5950: Part 1: 2000 (steel) and BS 5268: Part 1 (timber).

If we received an application using FEA as an analysis tool, it would probably be sent to an external consultant with FEA capability for checking.

VB

 

[40818]

mbga9pgf: I admire your intent to use some aerospace techniques and traditional methods, including the use of FE.
But firstly i would probably read up a bit more on FEA as your comment of "accuracies vary, depending on modelling method, number of nodes etc" is in itself innacurate, whether the number of nodes is 1 or 1 million, doesn't effect accuracy. The main cause of FEA innacuracies are due to user error. Also, be very carefull about using analysis techniques from aerospace in a civil environment.
Good luck though.

 

[csd72]

Mdga,

Be careful to avoid:

Measuring with a micrometer
some that will be
marked with a crayon and
cut with a chainsaw.

Construction does not have the same level of quality control that the aerospace industry does. Most of the safety factors in the design codes are to allow for the tolerances resulting from this.

A couple of specific comments on your design:

1. dont forget to allow for the creep properties of timber - particularly for those curved columns.
2. the same columns will definately be too slender on the flat as shown to make this work the small dimensionsion would need to be at least 75mm thick, if not more.

Hope this helps.

csd

 

[apsix]

"Guessing some blunty beaurocrat wont want anything as innovative as that built in the UK though... far too interesting."
I'm guessing you don't know what's being built in the UK.

http://www.wealddown.co.uk/gridshell-green-oak-timber-modern-architecture-10.htm

 

[mbga9pgf]

Yes, I have seen thatbuilding if anything that building in particular was one of the reasons that interested me in seeing how the planning office cope with applications including FEA.

That structure is not residential, its a workshop. I was interested in seeing if the planning office have any RESIDENIAL applications including FEA as a means of establishing whether regs are met.

Sorry if I have offended you, I did not intend to... it was meant as light banter. doesnt get around the fact that a lot of new extremely legislation has come in since 2000 (some could say overkill) which means the planning process has become overly complicated and vastly more expensive.

 

[csd72]

mbga9pdf,

I fail to see how it makes any difference whether the project is residential or not. It will be the same people looking at it in the building department.

csd

 

[apsix]

mbga9pgf
I'm not a Brit so I'm not offended.

I believe valleyboy has answered your question.