2nd Floor Cantilever Area Shear Transfer

Question

2nd Floor Cantilever Area Shear Transfer

Supun93 (Structural)

(OP)

1 Aug 24 17:49

I have a 2 ft cantilever floor in my ADU. How can i transfer shear loads from that cantilever wall to ground floor shear wall. We have a 2 ft overset. Thanks

ChorasDen (Structural) · Answer 1 · 2024-08-01 18:19:27

Use the floor diaphragm. It may require reinforcement through blocking or a double sheathed design, but that's you to determine based upon the loads that need resolved.

driftLimiter (Structural) · Answer 2 · 2024-08-01 18:22:41

There is also an unbalanced moment caused by the offset, the transfer region needs to act like a 3-sided diaphragm.

Supun93 (Structural) · Answer 3 · 2024-08-01 18:54:29

How can i design the blocking for the diaphragm? Any guidance?

ChorasDen (Structural) · Answer 4 · 2024-08-01 19:00:44

What does your local code tell you? In the US, we would reference the NDS SDPWS for capacities and detailing, but if you're outside of the US, you'd want to find the applicable code requirements and checks for your specification detailing situation.

To add some more context, the blocking provides load transfer from panel to panel, so generally speaking flat 2x_ material is the blocking of choice for most blocked wood diaphragm applications.

Drift is spot on as well, you'll need to check for torsional loading with a semi-rigid approach to determine stresses in the diaphragm and appropriately detail if/where blocking is required. With a 2ft cantilever however, I would not expect significant requirements, the IRC may even allow that short of a cantilever diaphragm with braced wall lines?

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2nd Floor Cantilever Area Shear Transfer