5/8" OSB Roof Diaphragm Allowable Shear
5/8" OSB Roof Diaphragm Allowable Shear
(OP)
Based on the gravity loads (Dead = 25 psf, Live = 16 psf, and Snow = 150 psf) and truss spacing = 16" o.c., the roof sheathing has to be 5/8" Str. 1 OSB.
I have determined the shear demand for the roof diaphragm (when determining the seismic shear loading, the snow load can be reduced by a third according to the local codes).
However, the UBC Table 23-II-H only goes to 15/32", so I am kind of struck...
Are there any other resources w/ tables for determining the nailing shedules/blocking for thicker panels?
Thanks,
cmhski
I have determined the shear demand for the roof diaphragm (when determining the seismic shear loading, the snow load can be reduced by a third according to the local codes).
However, the UBC Table 23-II-H only goes to 15/32", so I am kind of struck...
Are there any other resources w/ tables for determining the nailing shedules/blocking for thicker panels?
Thanks,
cmhski





RE: 5/8" OSB Roof Diaphragm Allowable Shear
www.awc.org/pdf/2001WindSeismicSupp.pdf
RE: 5/8" OSB Roof Diaphragm Allowable Shear
Thank you, but that does not answer my question...
I have already determined my required span & gravity load capacity. The seismic shear demand controls, not wind (seismic zone 4 + snow).
Once again, ASD Table 4.2A only goes to 15/32" thickness for Str.1, which does not help me with my 5/8" thickness - looking at the table, it is obvious that the shear capacity increases with thickness, so it would be nice to have a source providing the capacity for thicker panels, instead having to go with the conservative assumption of using the capacities of 15/32" Str. 1, and then having to specify a really close nailing pattern.
cmhski
RE: 5/8" OSB Roof Diaphragm Allowable Shear
The tables only go so far because that may be the limit of the approved testing. So to take advantage of a thicker panel, you'd have to go through a testing procedure and get ICBO approval of it.
I note that the IBC 2000 has table 2306.3.1 which includes 19/32" panels. But this would not apply if you are under UBC.