Tuesday, November 17, 2009

Can 2x6 T&G roof or floor consider to be a diaphragm?

1. 1.  I have a 1945 building and it has 2x6 T&G (2" Vert. and 6" Horiz) roof and the floor is nailed directly to beams at 54"o.c.  Can I consider these are flexural diaphragms with 54" existing nail spacing?

 

2.  2.  What about additional floor or roof joists that were added @ 18" o.c. with new nails at 18" o.c.  Will this be considered to be a diaphragm?

 

3.   3.  Or ½" plywood shall be added on top of existing 2x6 T&G?

 

4. 4.   The drawing plan called out some live load for Storage in 1945.  However the hand created drawing was not so clear to read.  I could not read the numbers if it's 50#, 75#, 100#, or 125#.  Does anyone know what was the 1945 UBC required for this year?