Wood Post Unbraced Length 2

[XR250]

To determine the capacity of this slender post (without getting into composite action), would you consider it as the twice the capacity of a single stud with strong axis buckling as the limiting factor. (i.e the weak axis is braced to equal the strong axis)

 

[Aesur]

I would typically just double the capacity of a single member and call it a day, however I wouldn't be surprised if Perp bearing actually controls assuming this is bearing on a plate.

 

[lexpatrie]

I wouldn't count this as a double, but ignore the strength of one and consider it as a brace for the other. This is a T-brace that is established practice in the fabricated truss design sphere.

Not sure I've seen any testing on this approach, however.

 

[bones206]

I recently made a spreadsheet for reinforcing wood trusses and in the process came across a research paper on T-braces (Shrestha, Deepak; Bender, Donald A; Woeste, Frank E.):

https://www.proquest.com/openview/118c13467d104d840c2424f6bacd9a87/1?pq-origsite=gscholar&cbl=25222

The approach in the research paper is to determine an overall effective modulus of elasticity for use in buckling equations. I ended up just calculating the radius of gyration and gross area of the combined section and going from there using the normal tabulated Emin.

Edit: and I take Lu as the overall length of the member, unless there are discrete braces or sheathing attached.

 

[lexpatrie]

I read that wrong a minute. Got thrown off by the commas and thought you had Donald Woeste....

I'll check that article out, yeah I had some wood truss reinforcement a while ago, too.

Ah crud, first page only via that link.

 

[bones206]

Full article:

 

[lexpatrie]

As a side note, XR250, the 10d nail you're showing. Common? Box? Sinker?

The research cited uses a 16d box nail (3.5" x 0.135") @ 6" o.c. into the brace element. First nail is 3" from the end of the T-brace.

Does anyone have a source for nailing for scab bracing (where the brace piece is flatwise against the web)? I feel like I found it somewhere once, but I've since lost my source.

Might have found it.

AUGUST 1, 2016 | SCAB-BRACE DETAIL | MII-SCAB-BRACE

For those who are interested, I found a Mitek detail for a T-brace with nailing that's not consistent (less) than the Woeste nailing (2011 document). It uses 10d nails. 3" x 0.131" is a sinker?

AUGUST 1, 2016 / I-BRACE DETAIL WITH 2X BRACE ONLY | MII-T-BRACE 2 | T-BRACE

On a related note, I know a while ago there was some pretty detailed thread on gable end bracing. I seem to have found something relevant to that discussion, so if anybody knows where that thread was/is, let me know.

Otherwise - this has the same Mitek detail (August 10, 2010 date), as well as several other details.
This is from Shawnstarrcustom homes. com, and it's about ten pages of Mitek details and some Weyerhauser catalog pages and some Forte output.
DB16-Truss-Notes, Feb 2023

 

[dik]

I'd use PL Premium and treat it as a T.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[bones206]

@lexpatrie - for detailing the T-reinforcement, I use the prescriptive IBC requirements as a baseline.