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Re: Lumber Moment Frame Connection

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Jim,
 
Knee braces are not a "code-approved connection" either.  The code may disallow some type of connection, but this is your case. Therefore, the planchecker's argument does not appear valid.
 
Your case is not that easy to win, formally.  Indeed, the shrinkage of wood and loosening of the bolts will eventually deprive the lumber connection of its initial moment resisting status. 
 
However, if your analysis proves the adequacy of connection, you may take it to the supervisor or to Building Official.  It worked for me several times; if it would not, you may always go back to knee braces.
 
Whether the possible victory is worth the battle - is a different story.  For a "shed", you may want to just use the knee braces, or cantilevering columns, saving time and avoiding aggravation. 
 
V. Steve Gordin, SE
Irvine CA
 
 
----- Original Message -----
To: Seaint
Sent: Wednesday, February 28, 2007 17:44
Subject: Lumber Moment Frame Connection

    Last week a county plan check engineer (Southern California) refused to consider a connection detail using custom steel "T" straps 3/16" thick on both sides - connecting a 6 x 12 beam to a 6 x 6 lumber column ( 2 each 5/8" dia machine bolts in each leg of the "T" Straps).  The lateral force on the simple shed roof 8 foot high patio cover was 2,240 foot- pounds.  
    The plan checker insisted that unless the client would be willing to use bolted lumber "Knee Braces" they would not issue a building permit.  Stating that there is no code approved heavy timber moment frame connection. 
    Your comments please.
 
Jim L. Chatterley PE
Composite Framing Systems, Inc.
2723 Currier Ave., Simi Valley, California, 93065
805-520-3666   Fax 805-583-1434
www.Compositeframingsystems.com