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RE: MBR Tie-Down System

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There is a holdown system called the "Earthbound System" out of the Seattle 
Area which incorporates a high strength connector/fastener that compensates 
for wood shrinkage.  They can be reached at 800-944-5669.  I know their 
system is competitively priced in comparison to other holdowns and they 
have their ICBO ER#.

Ed Chin, PE

From: 	T[SMTP:vicpeng(--nospam--at)]
Reply To: 	seaoc(--nospam--at)
Sent: 	Monday, March 16, 1998 5:07 PM
To: 	seaoc(--nospam--at)
Subject: 	Re: MBR Tie-Down System

What's the answer I wonder?

Thor Tandy  P. Eng
Victoria  BC

Subject: RE: MBR Tie-Down System

>You are correct that even holdowns that anchor floor to floor will loosen
>from shrinkage because floor joists will experience much more shrinkage
>than the vertical stud portion because of wood grain direction.
>I agree that TJM products shrink less than sawn lumber, but depending on
>the environment, swelling will occur between when the TJM's are produced
>and when it makes it to the job site (especially stored outside in a moist 
>environment!).  So over time, shrinkage will occur and holdowns will 
>loosen again.
>Subject: RE: MBR Tie-Down System
>>I've seen a building in the Seattle area which is a five story 
>>that suffered extensive exterior wall water intrusion because of some
>>flashing and sealing issues around the windows.  When the General
>>Contractor opened up some shear walls, he found the holdowns were loose.
>> The threaded rods were pretty much sloppy in the stud bays.
>The problem occurs even if you anchor floor by floor.  I have usually
>specified that the anchors be tightened regularly during construction (I
>never specifiy full buildng height anchor rods because of shrinkage) with 
>final turn and nut-locking immediately before closure.  By that time 
>a number of months) I estimate less than 1% remaining shrinkage.  Over the 
>depth of a floor (10" +/-) I figure the amount of slack will be minimal?
> With TJM products there is almost no shrinkage.
>Thor Tandy