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Re: SEISMIC ANCHORAGE

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Steve,
 
I am also interested to see how other building officials and design engineers weigh in on this.  You have painted the situation pretty accurately with regard to adhesive anchors, but remember this also affects mechanical anchors.  There are a handful of mechanical anchor products (actually only our DUC anchor in ICC ESR 1970 and a few Hilti anchors) that can be used in accordance with the newer I codes and the 97 UBC High Seismic zones (listed by ICC ES).  The mechanical anchor test standards including ICC ES AC 193 and ACI 355.2 have been around a little longer, so manufacturers have had more time to respond with the necessary testing-  and this testing is at a level of complexity never seen before.
 
Because ACI 355.2 only covers cast in place and post installed mechanical anchors, ICC ES has developed AC 308 to cover adhesive anchors.  As I mentioned above, this is a newer standard and even more extensive than the ACI355.2/AC 193 test requirements.  Manufacturers are currently in testing to comply with these reuirements.  Also note, the ICC ES will be cancelling all adheive anchor reports for concrete applications that are based on the older AC 58 testing on January 1, 2008.
 
I was also suprised to see ICC ES only recognize the current products to the lower seismic zones for the 1997 UBC and 2000 IBC, even though they have been previosly recognized for Zones 3 and 4, based of course on satisfactory performance in the AC 58 seismic tests (see ICC ES ESR 1702 for our CIA-GEL 7000 and CIA-EA adhesive anchors).  This is not clear to me why this was done.  In our report ESR 1702, Section 5.10, there is some background for the reasoning to limit seismic applications for the 2003 and 2006 codes, but the section also goes on to explain why seismic applications will be allowed for the 1997 and 2000 codes (however limited to Zones 0, 1, and 2A by Table 24). 
 
I think that what it comes down to is the wide difference in the way anchors are looked at now.  Running tests in cracks in accordance with the new test standards, and in uncleaned/partialy cleaned holes, indicates that there is the possiblility for much lower anchor performance.
 
Long winded response that doesn't really solve your immediate problem...  hopefully building departments will be slow to implement these requirements and give the manufacturers a chance to catch up with the adhesive anchors.  In the meantime, we do have the DUC anchors ;).
 
Howard Silverman, PE
Anchoring and Systems Research Engineer
Covert Operations/USP Structural Connectors
www.USPconnectors.com
hsilverman(--nospam--at)uspconnectors.com
 
 
-----Original Message-----
From: mailbox(--nospam--at)sgeconsulting.com
To: seaint(--nospam--at)seaint.org
Sent: Mon, 26 Feb 2007 9:52 AM
Subject: Re: SEISMIC ANCHORAGE

Robert,
 
The change in testing procedures is quite sweeping (refer to Ben Yousefi's post), and affects both the IBC and UBC.  Please refer to http://www.icc-es.org/reports/pdf_files/UBC/5369.pdf, Table 5.  Similar provisions now exist for all other HILTI epoxy anchors.  Moreover, according to HILTI engineers, it is also so for similar anchors of all their competitors (this is why HILTI is not that worried about such condition).  Looks like we are left out in the cold...
 
V. Steve Gordin, SE
Irvine CA
----- Original Message -----
From: Rob Randig
To: seaint(--nospam--at)seaint.org
Sent: Monday, February 26, 2007 09:24
Subject: RE: SEISMIC ANCHORAGE

Good morning Steve,
Could you be a little more specific.
What code changed, what eliminated the ability to use epoxy for
anchorage of all thread rods?
Is this an IBC thing or UBC or other?


Robert Randig, P.E.
 
 

-----Original Message-----
From: S. Gordin [mailto:mailbox(--nospam--at)sgeconsulting.com]
Sent: Monday, February 26, 2007 9:11 AM
To: seaint(--nospam--at)seaint.org
Subject: SEISMIC ANCHORAGE

Good morning.
 
Starting January 1, 2007, all HILTI epoxy anchors are effectively
excluded from usage in the areas of high seismicity (UBC Zones 3 and 4,
or IBC equivalents).  Apparently, this situation affects all (not only
HILTI) epoxy anchors, and the timing to resolve that situation is
currently unknown.
 
This means that no ICC reports are currently available to support the
engineers decision to use chemical anchors in the areas of high
seismicity.
 
Does anybody have the experience of dealing with such situation during
the plancheck?
 
Thank you,
 
V. Steve Gordin, SE
Irvine CA   
 
 

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