Timber frame construction, Scotland

[saveasteading]

(Wrong overall heading as the menu isn't working for me.)

 

Does anyone know if the design document "The Small Buildings Structural Guidance, 2010", has been withdrawn or discredited in any way?

It is still published online by the Scottish Government.

 

Our Engineer says , with a scoff, that it is no longer used or acceptable.

[Gus Potter]

Remarkable response from an Engineer to dismiss a Client in this manner with no apparent explanation. If a reasoned explanation was given the there would be no need to "scoff"

 

However here lies the rub and maybe "scoffing" was not the appropriate response.

 

Yes the small buildings guide is under review. I know that @saveasteading has a particular interest in this so have included a link at the end of this text to download the latest guide available online. I also attach the document I have down loaded using same link.

 

Page 3 of this document contains the critcal text that deals with the withdrawn aspect of "SBSG"

 

In my view paragraph 2 is misleading. Many of the BS Standards have not been withdrawn as suggested. Some have, in particular the wind / snow code but much of the timber design codes are still valid but with a few nuances.  It is for example perfectly acceptable by BC all over the UK to design to BS 5950 for hot rolled steel provided you take into account the latest available information in the euro codes.  A specific example here is that the Eurocodes require a haunch sharp end stiffener check/ design in a portal frame when in the BS left this open to the designer to check.

 

Paragraph two then introduces uncertainty and contradiction. It says that the designer should take care when using this guidance.. it does not say that you can't use it. BC say that this guidance has been removed from the technical hand book. So what! Provided you can produce a reasoned, valid and safe design based on the latest available information it is ok Just because BC have removed this from their guidance does not invalidate understood Science and Engineering skill.

 

Paragraph 3 is pretty much a rant but finishes by saying that as Designer you can do what you want provided you can prove it is safe.

 

In my view it is still ok to use the SBSG as a basis for design provided you recognise where the changes in wind load / snow loading may impact on the guidance. It still is a good document for preliminary design.

In actual fact unless you live at a high altitude for example in the UK the Eurocode changes will have little impact on the guidance. The wind may have a slight differance but generally it is the dead weight of the roof covering and the access load / deflection under normal loading that will goven the design anyway.

 

For any Enginner not to discuss and offer reasoned explanation to a Client when specifically asked is a disgrace to the SE profession.

 

Gus Potter.

 

 

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjD6Z7ftcn2AhWVQkEAHfBJARwQFnoECAcQAQ&url=https%3A%2F%2Fwww.gov.scot%2Fbinaries%2Fcontent%2Fdocuments%2Fgovscot%2Fpublications%2Fadvice-and-guidance%2F2020%2F02%2Fthe-small-buildings-structural-guidance%2Fdocuments%2Fsmall-buildings-structural-guidance%2Fsmall-buildings-structural-guidance%2Fgovscot%3Adocument%2FSmall%2BBuildings%2BStructural%2BGuidance%2B%2B.pdf&usg=AOvVaw2nnn0liJPfV762mn9NosnA

1226535124_SmallBuildingsStructuralGuidance(3).pdf

[saveasteading]

Thanks Gus. The fact that this document was revised in 2010 to state that the BS guidance was withdrawn, and Eurocodes now prevail is, to me, the fundamental part. If it was not to be used it would not have been published, but withdrawn.

 

When Eurocodes were introduced my main interest was in steel. The Eurocodes were much more up to speed on local wind effects, use of tapered frames, flange bracing and many other issues. 

I had many a building inspector / checking engineer/ client's Engineer saying that they would rather we used BS as it was easier for them, something they had been working with for years, and provided the comfort, to them, of using a lot more steel.

 

BUT in all this we still had to use British wind and snow codes, and most countries did the same.

ie the Eurocodes prevail but many countries added their own rules.

 

I won't quote the differences I learned about, but there were many, based on local circumstances or simply feet dragging.

 

My main concern re SBSG was that it had been quietly withdrawn, and the government had forgotten to take it off their website.

 

As it happens, our provided design isn't too bad on the timber construction, but we have big arguments re the foundations and slab, where they add £15k or more to our cost. It is under discussion, but I don't think the Engineer has ever been questioned before.