Double Top Plates as Diaphragm Chord
Double Top Plates as Diaphragm Chord
(OP)
I'm currently working on a wood mezzanine and not visualizing how the diaphhragm chord forces will be resolved. I understand the theory behind the forces, but just don't see how the load path runs from the plywood nailing, down through the blocking/rim joist, and into the top plates. My joists are 16" deep so am I really supposed to believe that a 16" deep 2x4 block will transfer this tension force down into the plates? It seems too tall. Should I use 4x blocking and strap across the sheathing underneath the upper floor sill plate or should I strap across the blocking on the outside underneath the shear wall plywood? Any advice?






RE: Double Top Plates as Diaphragm Chord
To transfer lateral forces, you need blocking panels fitted between joists. See some of the many TJI catalogs for more information.
BA
RE: Double Top Plates as Diaphragm Chord
It fills the void between the joists, and between the top plate and underside of the plywood. You really need to use TJI blocking here as suggested.
Mike McCann
MMC Engineering
RE: Double Top Plates as Diaphragm Chord