It has always been my opinion that blocking serves two purposes:
1. A fire block - in which case it should be set tight.
2. To transfer shear at the unsupported ends of staggered panels in high
loaded walls. In this case, I believe that all blocking should be tight.
Stud buckling in the weak axis is not much of a concern since the stud is
considered continuously [laterally] supported by the connection of the
sheathing. The more critical concern is buckling normal to the wall which is
generally the studs strong axis.
As I recall from a past thread by John Rose or another authority on wood -
shrinkage is not much of a consideration from end to end, but rather occurs
noticeably in member depth and possibly its width. In other words a 14" long
2x4 will shrink in the 4" dimension but very little in the 14" dimension.
Possibly others can help with my memory.
Dennis S. Wish, PE
From: George Richards, P.E. [mailto:george(--nospam--at)BORM.com]
Sent: Friday, March 10, 2000 9:09 AM
Subject: RE: shear wall blocking
And lets add one more question. If the blocking is green when installed do
we take 70% of tabulated shear values per the NDS? My understanding is that
the code values are based on dry lumber tests.
From: David Hall [mailto:Dahl(--nospam--at)deainc.com]
Sent: Friday, March 10, 2000 8:50 AM
To: jwatson(--nospam--at)inconnect.com; seaint(--nospam--at)seaint.org
Subject: Re: shear wall blocking
A question to answer a question..... I had always though that blocking.....