CMU Shaft Wall Wood Ledger

[JoshH726]

4-story wood frame structure in upper Midwest (no seismic) with interior CMU shaft walls 8’x10’(away from exterior walls) for small MRL elevator. CMU shaft wall is not being relied on for lateral resistance. Shaft wall is at the intersection of perpendicular corridors 6’ wide framed with 2x joists, otherwise spanning between 2x bearing walls with LVL top and sill plates.

LVL ledger to pick up corridor joists, with ledger then being mechanically fasten to CMU wall? Thoughts or concerns on differential movement of CMU relative? LVL ledger should mitigate cross grain shrinkage. But how to account for potential differential movement of the CMU? Is it quantifiable? One thought seen is to set LVL ledger 3/8” lower (or some fractional inch) than floor elevation? Not sure on that but open to alternatives. Thanks in advance.

 

[jayrod12]

CMU likely won't move as much as the wood structure will shrink. At a rate of about 1/4" per floor. I find having the framing coming into the wall at the door allowing it to hinge at the door normally works well, and then often don't connect it on the other sides at all. Frame around it like an opening.