Timber Frame Houses 1

[rnorth]

Hello,
I have been approached by a timber frame manufacturing company that needs engineering services. I have some experience in wood design but have not designed a timber frame before. was wondering if anyone on this site could offer any advice. tongue and mortice joints are used, white pine or oak seems to be the material of choice.
TIA

 

[SteelMover]

From what I understand its fairly specialized. I know these guys know what they're doing:

http://www.nehilsivak.com/

It's a passion of Tom's, one of their principles. Maybe they could perform some design review for your first few attempts until your get your feet wet.

 

[MiketheEngineer]

I have done two .... and was sadly disappointed by the info supplied by the mfgs!! Some didn't even know what grades they were using. Some say they had "engineering" - but when I reviewed it - obviously it was most inadequate. One even admitted his design was at least 33% over-stressed.

Of course - they always say "We have been doing this for years w/o any problems" And that is probably true..

They mostly sell in uncoded or unenforced areas.

My suggestions:
Get complete plans
Get "any" engineering they say they have done
Get exact timber specs
Get framing details
Get all anchorage details
Etc, Etc, Etc.

Actaully - the only way I showed one OK was becasue they were using tested SIP roof and walls and it did work OK - just barely

The other - after some quick calcs - I refused - way out of line.

These can be VERY beautiful structures - just make sure the engineering falls in line....

Really - if you can get roof diaphrams and shear walls working - they will be just fine.

 

[DaveVikingPE]

Do you have a good timber design text? And... do you have the National Design Specification for Wood Construction (NDS)?

 

[structuralaggie]

http://www.timberframe.org/Publications.aspx

This is the only real desing criteria I have found, but some are not very impressive. The biggest debate is what is the allowable load a wood peg can take. On paper went through great lengths to determine what mode of failure would control design, similar to the NDS equations for double shear on bolts, and concluded that it was the wood peg that controlled, and further anlaysis would be required. Hello McFly, News flash! Of course the wood peg design controls.

Other info here:

http://www.tfguild.org/

The biggest problem with these things is the connections. The members themselves are usally massive compared to what is required by analysis.

The main thing to keep in mind is do design for compression only. Small tension forces can be handled, but for the most part you need to make the configuration of the frames work for compression. Where you have significant tension, you will have to get creative and hide some steel. If your timber framer is any good, he can help you with this.

I would push for making them conventionally frame walls on the exterior so that you can make shear walls. I am not a fan of the SIP's where lateral loading is concerned.

 

[BSE05]

Bensonwood Homes, Walpole, NH is a post and beam company with structual engineers on staff. One of the best companies around.

I've investigated a couple of post and beam structures gone bad. Definitely their own specialty.