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RE: BOLT- Epoxy Anchors

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SInce I work for Hilti I am, of course, not biased on this subject at
all.  However, I will throw in my two cents worth.  First, the HVA
system is just one type of adhesive anchor.  Epoxies are also used as
adhesive anchors, but the HVA is not technically an "epoxy anchor."

There are many different materials out there that are marketed for
anchoring.  Some have very good resistance to temperature changes and
weathering, others do not.  Many properties of the materials effect
these charachteristics- Modulus of Elasticity, Heat Deflection
Temperature, Elongation at break.  Epoxy products, for example, tend to
have a low heat deflection temperature which may effect their ability to
withstand higher temperatures.  In order to save everyone from having to
sort out all of these material properties, ASTM has published "Standard
Test Methods for Testing Bond Performance of Adhesive -Bonded Anchors",
ASTM E-1512-93.  Several tests outlined in this standard deal with
in-service conditions.  Probably the best one for your question is
section 7.9, Tests for the effects of freezing and thawing conditions.
The test subjects submerged anchor samples to 50 cycles of a 114 degree
temperature swing (from -10 F to 114 F.)  The samples are then tension
tested and compared to baseline (room temperature) samples.

The bad news is that this standard is that it is a test standard only,
not a performance standard.  So you or someone else has to evaluate the
results and decide if they are acceptable.  We have been doing these
types of tests for a long time on our adhesive anchoring products, and
have a good feel for their performance.  The HVA system, for example,
performs very well under freeze-thaw conditions, as well as other
enviornmental tests like long-term creep at elevated temperatures.

If you are looking for something more independent, ICBO ES has adopted
an acceptance criteria for Evaluation Reports for adhesive anchors known
as AC 58.  Part of the criteria provides pass/fail requirements for the
various ASTM E 1512 enviornmental tests, including freeze-thaw and creep
at elevated temperatures.  If a product does not pass, for example, the
very freeze-thaw requirements, then it will be restricted to interior or
protected locations.  Unfortunatley, only the very latest reports
(within the last year or so,) were evaluated under AC 58.

The bottom line is that any reputable manufacturer should have already
performed these types of tests before introducing a product to the
market. They should be able to provide the data.  If they hold an ICBO
report, you should ask them if it was evaluated in accordance with AC
58.  (Our report for HVA, No. 4016 for example, was not, because AC 58
was not in existence when the report was done.)  ICBO is requiring that
certain enviornmental tests be done even on existing "old" reports, but
this process is not complete.  It is probably best to just call the
manufacturer and ask.  Even if they do not have a new ICBO report, they
should be able to provide the data.

	Please feel free to contact me directly if you need more

	Chris Gill
	Hilti, Inc.
	Manager of Field Engineering


> ----------
> From: 	rlewis(--nospam--at)[SMTP:rlewis(--nospam--at)]
> Sent: 	Monday, October 20, 1997 1:24 PM
> To: 	seaoc(--nospam--at)
> Subject: 	BOLT- Epoxy Anchors
> I haven't seen much in the way of published literature on this subject
> so I
> want to pose the question to the list server.  I am considering using
> epoxy
> anchor like Hilti's HVA Adhesive System anchors.  The Contractor on
> one of my
> projects missed one of the column anchor bolt location by about 9
> inches. 
> Not much to do now except drill in new anchors.
> My question concerns the longevity and proposed application of epoxy
> anchors.
>  How long are they expected to last.  Specifically, my column is
> located
> outside the building and wrapped in masonry.  It will be exposed to
> the
> seasonal temperature variations of Dallas, TX.  Does normal seasonal
> temperature variation affect the anchor bond?  Are there published
> limitations to the use of epoxy anchors?
> __________________________________________________
> Richard Lewis, P.E.
> Missionary TECH Team
> rlewis(--nospam--at)
> The service mission like-minded Christian organizations
> may turn to for technical assistance and know-how.