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Re: Overhead anchors

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Fellow engineers,

        Why not use non shrink or expanding cement based grout for this
application?  I would expect this type of material to work very well.

Respectfully submitted,

H. Daryl Richardson

Forrest Braun wrote:

> William
>
> On various Corps projects that I have worked on adhesive anchors were
> not allowed.  The argument was that 1) epoxy will allow creep such that
> under long term tension loads the anchor will pull out, 2) keeping the
> epoxy in the overhead hole during installation is difficult, and 3)
> under elevated temperatures or fire conditions the epoxy will loose
> strength and release the anchor creating an additional hazard.  Some of
> the acrylic adhesives solve the temperature and creep problems but may
> still have the installation problem.  Expansion anchors were accepted
> for overhead conditions.
>
> "Sherman, William" wrote:
> >
> > Engineers in our office have expressed concerns with using expansion anchors
> > in overhead applications, such as hanger supports, due to the potential of
> > long-term slippage under constant tension. I do not see any cautions noted
> > on the use of expansion anchors in such applications in manufacturer's
> > literature or in ICBO reports. Does anyone know if there is documentation of
> > slippage of "friction-type" anchors in constant tension applications?
> >
> > We often prefer to use adhesive anchors in overhead applications, when
> > drilled-in anchors are required - but concerns have also been raised with
> > such anchors due to the potential softening of the adhesive in case of a
> > fire. Also, overhead installation of adhesive anchors is more difficult.
> > Does anyone have other recommendations for application of post-installed
> > anchors in overhead applications?
> >
> > William C. Sherman, PE
> > CDM, Denver, CO
> > Phone: 303-298-1311
> > Fax: 303-293-8236
> > email: shermanwc(--nospam--at)cdm.com
> >
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> --
> ++++++++++++++++++++++++++
> Forrest T. Braun, P.E.
> BBFM Engineers, Inc.
> Ph (907)274-2236
> Fx (907)274-2520
> Anchorage, Alaska
> http://www.bbfm.com
> ++++++++++++++++++++++++++
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