IBC shear wall table used for a diahragm?

[JAE]

Table 2211.1(1) in the IBC 2000 shows values for shear in plf for wood sheathing attached to metal studs in shearwalls.

My question is - would this work for horizontal roof diaphragms? I know that the IBC (and UBC) provides separate tables for wood stud/wood sheathing shearwalls verses horizontal diaphragms ... but isn't the principle the same in terms of raw shear in a framed panel?

 

[Lutfi]

JAE,

You are making me wonder about this. One obvious fact is that we use blocking in the roof which gives differing shear values. I don’t have my code with me, but I do not recall that the wall tables have provisions for blocking? Do they?

 

[JAE]

No - I don't think that the wall tables have blocking required always...but if you did block (as in a roof) you would most likely have higher values than lower...thus, using a shearwall table for a diaphragm would be conservative, no?

 

[haynewp]

Table 2211.1(1) says "fastener spacing at panel edges" so wouldn't that require blocking?

It looks like comparing the diaphragm to shearwall tables in chapter 23 gives close values for the blocked diaphragm case.
But in general the diaphragm table lists a little less allowable for 2" support members and a little greater value for 3" support members compared to the shearwall table values that are based mostly on 2" minimum support members.