Length of straps above openings of force-transfer shear wall (shear wall with opening)

[LockeBT]

NDS requirement: Collectors for shear transfer shall be provided through the full length of the force-transfer shear wall.

I have seen straps above the opening(s) that run the entire length of the shear walls. I myself only provided straps long enough to distribute the force into the adjacent wall piers since that full length collector aforementioned is basically my double top plates. Am I correct in this assumption?

Thank you,

-Locke

 

[SJBombero]

I think that is the correct understanding. A collector is a member which delivers load from the diaphragm to the LFRS. The straps on an FTAO wall would not be considered collectors. Figure 4E in the SDPWS also shows a situation in which a full-length strap would be impossible.

 

[jdgengineer]

You only need to run the straps the length you need to develop them but if they do not run full length you need to account for the additional wall stress on the shearwall segments as they are taking a concentrated load from the straps.

Personally, we run them full length to avoid this. If they are really long straps you may want to consider if a perforated wall can work instead.

 

[LockeBT]

Thank you!