We use T1-11 predominately in Hawaii, but I too have never seen a rated
shear capacity via an ICBO report or similar. I assume I've been safely
conservative to use 3/8" CDX plywd nailing strengths when used as a shear
sheathing material, since the nailing generally occurs in 5/8" material.
I suspect test values would be somewhere between values for 3/8" and 5/8"
If you find any ratings, please let me know, too? Have you searched APA
BTW, a word of warning about grooved T1-11. Panels with 8" groove
spacings have led many contractors to install sheets with 8" edge
nailing, rather than 6" on center, in my experience. This obviously
adversely affects shear capacities. In new construction, I now always
specify a maximum 4" oc edge nailing, which makes inspection easier, if
John P. Callen, SE