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Re: Expansion Anchors in Masonry

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At 10:54 AM 10/29/97 -0800, you wrote:
>Is anyone aware of an expansion anchor which has a current ICBO Report
>which addresses a masonry application?  ITW used to in their 1992
>version of Report #1372 but the 1997 version no longer addresses this
>application.  I contacted the local ITW rep and he said that they did
>not resubmit the masonry application on purpose.  Apparently they
>figured no one else needed it (they ICBO approval) so why should they. 
>Our local code jurisdiction is taking the stance that there is no
>product presently available with a current ICBO Report and therefore
>they will not allow the application.
>
>Dan Burch


((Steve Gregg,PE)) I received a detailed (broadcast) letter (dated 10/1/97)
from Peter Waespi, a Hilti Field Engineer (Pacific Northwest)(1-800-879-6000
ext 7572) which addresses this issue.  Peter indicated that the ICBO
Evaluation Service (ES) now has a revised "Acceptance Criteria for Adhesive
Anchors in Concrete and Masonry Elements". In accordance, Hilti has
submitted data & evidence and received an ICBO Evaluation Report Supplement
(attached with Peter's letter) which clarifies several service condition
items (notably seismic applications) which weren't addequately addressed in
previous ICBO reports (for *any* adhesive anchor manufacturers) under the
previous Acceptance Criteria.  Apparently for all mfrs, the ICBO report
would state that (for adhesive anchors) anchors hadn't been evaluated for
wind and seismic forces (because ICBO didn't have a dynamic load criteria).

For *expansion* anchors, ICBO hasn't published a clarifying "Acceptance
Criteria" and so Hilti, along with all the other mfrs, have ICBO reports
stating that expansion anchors haven't been evaluated for wind and seismic
forces.  Peter included a copy of a letter (dated 9/2/97) from Kurt Stochlia
(VP at ICBO ES) to Martin Schofield (VP at Hilti) which addresses the fact
that ICBO hasn't clarified the Acceptance Criteria for expansion anchors
because they "do(es) not currently have dynamic load criteria for these type
of anchors".  Stochlia goes on to say that for this reason, they can't
comment on the numerous test data Hilti had submitted, and that "These
reports (test data from Hilti) could be used by an engineer and/or a
building jurisdiction to determine if the anchors are acceptable for seismic
loading conditions, if they so desire."

What I'm wondering is:  ***Why does the dynamic load criteria for an
expansion anchor differ from that of an adhesive anchor?***

It appears to me that: 1) ICBO is diverting liability to individual
consultants on this expansion-anchor-under-seismic-loading issue, and 2)
they are either tripping on red tape or they're not telling us something.



                        Steve Gregg, PE
                        SGC Engineering
                        P.O. Box 315
                        Walla Walla, WA  99324
                        (509) 525-6911 (voice or fax)