Wood Ceiling Diaphragm - Maximum Span??

[Serhiy2]

Hello there,

I'm designing a 80'x160'x12' wood building with gabled roof. I can get away with side walls and one interior wall going along the length of the building to be load bearing. I intended on using OSB ceiling diaphragm to transfer lateral loads to end walls (shear walls). I did preliminary calculations and OSB diaphragm seems to work. My quick diaphragm deflection calculation produced 17mm (11/16") of deflection which is h/215 but I'm sure I could get it close to h/500 (required by code) if I sharpen my pencil. Strength-wise it also works on paper. Building will have interior slab on grade with transverse walls with slip connections at the top to accommodate truss deflection so there will also be some un-quantifiable extra lateral resistance.

I'm a bit concerned with 160' long wood ceiling diaphragm and I'm thinking of adding shear wall somewhere in the middle. Wondering what you guys think on having such long wood ceiling diaphragm?

 

[jayrod12]

Hardest part is getting the load into the top of the walls properly... if you get that solved for the magnitude of load you're talking about, then I don't see the issue..

 

[txeng91]

I believe the only limitation is aspect ratio, which is 3:1 for unblocked and 4:1 for blocked. Refer to NDS SDPWS:

https://awc.org/pdf/codes-standards/publications/sdpws/AWC-SDPWS2015-ViewOnly-1508.pdf