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rockies
Member
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# Posted: 9 Jun 2016 07:40pm
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American Wood Council Design Guide
http://www.awc.org/codes-standards/publications/dca5
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Don_P
Member
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# Posted: 9 Jun 2016 08:37pm
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Good job 
I thought of that just a minute ago down in the shop, nfba.org is another resource.
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creeky
Member
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# Posted: 9 Jun 2016 08:39pm
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"Buried or embedded posts also can resist lateral loads by developing partial fixity. See figure 3."
Well hot diggity for partial fixity. Somebody get the fiddle. I feel like dancin'.
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Don_P
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# Posted: 9 Jun 2016 09:59pm
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Read the EP and you'll understand why I say to neglect the soil as being the thing that holds your posts upright.
Use the walls and diaphragms.
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Julie2Oregon
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# Posted: 10 Jun 2016 03:15pm
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Quoting: creeky Well hot diggity for partial fixity. Somebody get the fiddle. I feel like dancin'.
LOL! What on earth is "partial fixity"? I'm not sure that's English. Three cheers for jargon! NOT.
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Don_P
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# Posted: 10 Jun 2016 06:56pm - Edited by: Don_P
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Y'all are understanding I hope. Post frame CAN use the partial fixity of the soil as part of the lateral resistance, it doesn't have to and I wouldn't. That is the ONLY lateral bracing for most of the pier and beam builds we've seen... and techno posts, and sonotubes. Partial fixity sounds kind of like mud doesn't it. Someone pushing you to rely on partial fixity alone is peddling snake oil.
Now look at fig 4a. I poured a small slab on grade today for some friends pottery kiln shed. He is using that detail for the post frame. In that case the posts are out of the soil fully sheathed and braced to the connection with the foundation. (Aside, we worked together for about a year before he got his class A license, our other coworker got his electricians. We've decided that after a year a man will go get his license... or gnaw his leg off )
On the main DCA download page that rockies link takes you to, look on the left sidebar and download DCA6 if you don't have a copy. Since decks are not in the codebook they have developed these "designs for code acceptance" that many/most building departments will accept as if they were a part of the codebook. they would be considered "best practices" I suppose. This is one reason I try to point people in that direction, the other reason is the same reason it is heading towards becoming part of the code... it is structurally correct. You do not see a DCA for pier and beam. Look in DCA6 and you will see pier and beam and kneebracing for a freestanding deck with callouts for the bracing. Which is fine for a 50 pound per square foot deck load but obviously insufficient for bracing a structure's weight and sail area on top of those lightly braced posts.
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rockies
Member
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# Posted: 10 Jun 2016 10:37pm
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Don_P. Soooooooo..........what I'm picking up from your post of 18:56 is that people are using the type of pier foundation and beam connections mentioned in DCA6 (which are really meant for decks) and instead using them to build cabin foundations with and you don't agree with that.
As in my other thread about the concrete post columns, I sense that you don't like those either because the wooden posts are attached to the concrete columns with bolts and that high wind shear could snap the connection with the metal plate connectors.
In other words, you feel that the only method of doing a proper post frame building is to have the posts themselves go into the ground below the frost line and sit on concrete pads and then backfill.
How should the posts be connected to the concrete pads (or should they) and should you use partial concrete with soil on top to backfill or fill the entire hole with concrete.
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Don_P
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# Posted: 10 Jun 2016 11:10pm
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Actually we aren't seeing the level of detail called for in the deck guide even.
I like those. There are limits.
No
They should be connected to the foundation, not necessarily buried, with sufficient connection capacity to withstand... up, down, and sideways loads.
If you go to NFBA's website, find the webinars, find the introductories by Harvey Manbeck and watch them. He is also a good instructor you'll find his classes posted there and on the woodworks site (free lunch and ceu's too).
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