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RE: Anchor bolt sleeve - pretensioning

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I use a bond breaker.  I know that the major tank consultants use a bond breaker and hydraulic tensioners. 
 
The problem is not foundation failure as much as it is predictable lateral drift and cycling of the bolts.  If the bolts cycle, they will fatigue at a notch (the threads).  This is not a desirable mechanism.  I have observed broken anchor rods, and I have observed excessive drift because the anchor rods were not properly tensioned. 

Regards, Harold Sprague






Date: Mon, 2 Feb 2009 12:58:45 -0800
From: prajendran(--nospam--at)ymail.com
Subject: Anchor bolt sleeve - pretensioning
To: seaint(--nospam--at)seaint.org


In its section on anchor bolt with sleeves, the ASCE booklet "Wind Loads and Anchor bolt design for petrochemical facilities" recommends breaking the bond (by wrapping a tape) between the bolt and the concrete between the bottom of the sleeve and up to 1" above the bolt head. This is claimed to prevent loss of bolt pretension.

How many of you follow the above specification? I use standard sleeve and do not specify breaking the bond as recommended in ASCE. Are there any recorded cases of foundation failures which resulted from loss of bolt pretension?

Rajendran



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