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Re: Post frame building design

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Title: Re: Post frame building design

Wrt a requirement for perimeter foundation walls, I think that depends on what the local jurisdiction requires, and what the intended use is for the structure. For ag buildings, this system provides an economical structure that's structurally sound. Rodents and erosion are controlled by other "methods"  (e.g. BB guns and skid loaders).

;^{o

HTH

Buddy


From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
Subject: Re: Post frame building design

Informative articles, thank you. The pictures in these arcticles confirmed to me why this particular building is inadequate as originally drawn. The two major issues are that -

a) the gable posts stopped at the bottom of the gable truss, with no diaphragm bracing at the truss lower chords. There was nothing for these posts to lean on and no way for them to transfer lateral loads to the side walls. The architect was unwilling to extend them to the roof.

b) one of the building walls abutted another building and had no siding on it to act as lateral bracing.
These issues have now been resolved. Other issues like header sizes come down to simple engineering analysis.
My only remaining question is why these don't need perimeter foundation walls. If not for frost, at least for rodent and erosion control...

Thank you again,
Jim Wilson


AWC Info <AWCInfo(--nospam--at)afandpa.org> wrote:
Actually, this is a viable structural system if properly designed and constructed. The posts provide support for both vertical and lateral loads and the metal sheathing provides diaphragm action. Here are a few resources that might help:

http://www.awc.org/HelpOutreach/faq/FAQfiles/DCANo5.html
There is an article in a recent issue of Frame Building News that discusses a project where a full-scale post frame building was tested with lateral loads to better estimate the resistance provided by this system. Here's a link to the online article. You may need to register (free) to view it:

http://www.framebuildingnews.com/Default.aspx?tabid=1176&articleid=4235&articlemid=4855#4855Articles
HTH
Buddy
John "Buddy" Showalter, P.E.
Director, Technical Media
AF&PA/American Wood Council
1111 19th Street, NW, Suite 800
Washington, DC 20036
P: 202-463-2769
F: 202-463-2791
http://www.awc.org
The American Wood Council (AWC) is the wood products division of the American Forest & Paper Association (AF&PA). AWC develops internationally recognized standards for wood design and construction. Its efforts with building codes and standards, engineering and research, and technology transfer ensure proper application for engineered and traditional wood products.

*********************
The guidance provided herein is not a formal interpretation of any AF&PA standard. Interpretations of AF&PA standards are only available through a formal process outlined in AF&PA's standards development procedures.

*********************

From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
Subject: Post frame building design
I have been asked to review a set of plans for an architect designing a post frame building. The builder had a set of "engineered" plans from a post frame company, but didn't want to use them for whatever reason.

Those plans included a flat floor slab with no turned-down edges or footings on the perimeter, glulam pressure treated posts embedded in dirt with no concrete, no lateral bracing other than the 28ga metal over 2x4 girts spanning 8ft between poles, roof trusses at 2' with metal roofing over 2x4 girts at 2'o.c., no insulation, etc., etc. This hardly seems up to code or up to any engineering standard. Is there some magic about these buildings that they don't need normal structural building components? The building inspector already approved the original plan (presumably out of complete ignorance).

Jim Wilson, PE
Stroudsburg, PA