Post/beam shear transfer 1

[civilgene]

Hello-
Is there a way to transfer shear from a second story wall (new construction) that is supported by post/beam construction(new construction within an existing room)?? I have the post/beam designed for vertical loading, but need lateral loading resistance. Will the second floor diaphram provide any resistance? Any ideas??

 

[Lion06]

I would actually be more concerned about the moment resistance of the shearwall than the shear resistance. You might try adding a beam directly under the wall and anchoring to it. make sure the supports for that beam can take the uplift that will result from the applied moment (probably won't be a problem with the dead load).
As far as checking the diaphragm for this shear and mment, I am not really sure, but am very curious to hear from others.

 

[msquared48]

Transferring the horizontal shear from the shearwall to the floor diaphragm is normal. The tricks come where the floor diaphragm is not in contact with the shearwall throughout the length of the shearwall, necessitating reinforcing the diaphragm. The nailing and blocking of the floor diaphragm may have to be locally increased (sub-diaphragms). Additionally, the diaphragm will have to be strong enough to span out the shear forces to the existing shear walls below, or walls that need to be designated as such. Don't forget the holddowns either that may have to be retrofitted into the lower walls.

Assuming no moment connections are used, adding a transfer beam under the shearwall will not help with the lateral shear loads, only possibly lower the overturning forces to be resisted (if the beam is longer than the wall).

Mike McCann
McCann Engineering