Figuring for Wood Girts
Figuring for Wood Girts
(OP)
Hello all new here and to the industry.
I am trying to find any information on wood girt design. I am in the steel industry and have a customer that is using 2x10 wood for girts. The buiding is a 30LL 16' Bay Spacing, 90MPH Exp B building, 2' OC Purlin/Girts. His permit department needs our drawings to say that 2x6 will work for his girts although he is going to use 2x10's. Any help with this would be greatly appriciated.
I am trying to find any information on wood girt design. I am in the steel industry and have a customer that is using 2x10 wood for girts. The buiding is a 30LL 16' Bay Spacing, 90MPH Exp B building, 2' OC Purlin/Girts. His permit department needs our drawings to say that 2x6 will work for his girts although he is going to use 2x10's. Any help with this would be greatly appriciated.





RE: Figuring for Wood Girts
Even a 2x10 flat to the wind at 16' span maybe problematic.
Say 10 psf wind - minimum - adjust if needed
24'' o.c. = 20 plf
M = wL^2 /8
M = 640 ft-lbs x 12 = 7680 in-lbs
Fb = M / S Syy - 2x10 flat = 3.468 in^3
Fb = 7680 / 3.468
Fb = 2214 psi / 1.33 reduction for wind = 1665 psi
So you need a fairly good grade of 2x10. Some codes allow for a 1.6 wind reduction instead of 1.33. That will help if applicable.
I got you this far - now check for deflection - that could be a real problem.
Good Luck
RE: Figuring for Wood Girts
RE: Figuring for Wood Girts
The section modulus - Sxx - just went up to 21.4 in^3
SO NO PROBLEM - either in bending or deflection
RE: Figuring for Wood Girts
You either need adequate bridging to take this or you need to design them for biaxial loading and for buckling along the full length.
RE: Figuring for Wood Girts
Good Point - I am hoping sheathing will take care of that
RE: Figuring for Wood Girts
RE: Figuring for Wood Girts
RE: Figuring for Wood Girts
Regarding the twisting action csd refers to, just add vertical blocking at midspan. This coupled with the girt end connections should suffice.
Mike McCann
MMC Engineering