Does a diaphragm chord need to attach to the diaphragm? See attached image.

[Struct2468]

See the attached image. Can the CMU bond beam be considered the chord even though it doesn't attach directly to the wood sheathed diaphragm if there is proper attachment (e.g. connection via sheathing to blocking to nailer to bond beam)?

 

[JAE]

As long as ALL the associated elements and connections meet the diaphragm-to-chord load requirements, I would say yes.

 

[DaveAtkins]

Agree with JAE.

 

[driftLimiter]

The load path from the diaphragm edge nailing to the rim, from the rim to the sill, from the sill through the bolts must all have at least the same or more strength as the diaphragm edge nailing.

I don't usually worry about how additional flexibility due to this indirect load path to the chord effects the diaphragm deflection unless there are very flexible items in the load path. For example if instead of a rim joist you have shear wall, this may increase diaphragm deflection or at least the chord component of diaphragm deflection.

 

[Nick6781]

I think so as long as every element along the load path can transfer the compression/tension assumed in the chord