Wood Shear Wall - Prefab Panels/Common Framing Members 1

[UTvoler]

I have a wood-framed commercial apartment building in which the contractor stick-framed the first floor walls, and then switched to offsite/prefab wall panels for the remaining four floors. The prefab shear walls were sheathed offsite, and most of the shear walls were too long to be fabricated as a single panel and so were erected with butt joints. These were segments of walls with double studs at joints, and the sheathing did not lap over the joints. I noted this on a site visit, and told the contractor this was not going to be adequate. SDPWS2015 4.3.6.1 states "where shear walls are designed as blocked, all joints in sheathing shall occur over and be fastened to common framing members or common blocking". 4.3.6.1.1 goes on to state "where a common framing member is required at adjoining panel edges, two framing members that are at least 2" in nominal thickness shall be permitted provided they are fastened together with fasteners designed in accordance with the NDS to transfer the induced shear between framing members".

If I have 13 kip "induced" shear in a wall, does that mean I have to provide a fastener detail to join the two adjoining studs such that the fasteners resist 13 kip of withdrawal load distributed along the height of the wall? I guess that is my interpretation of the requirement, but it makes for a pretty heavy/nasty screw pattern on some of the second floor walls.

Thanks for any input/thoughts!

 

[KootK]

1) The demand at the fastened studs may well be considerably less than 13 kip. The demand should usually be calculated as the unit horizontal shear stress in the wall multiplied by the height of the studs.

2) For this, I believe that the fasteners are loaded in shear rather than withdrawal.

 

[UTvoler]

Thanks KootK, I think you're spot on! I should have drawn the free body diagram first....