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Re: Coring Concrete

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Talk to John olyar a Eng at Hilti Tel:1 281 798 8643 he can give you
some good answers.
                 Good luck Alan Pettingale

Mark Gilligan wrote:
> >>>Our current design involves drilling a 6" diameter hole and a 1 1/4"x
> 24"
> long anchor bolt and filling the holes with mortar. The contractor wants to
> core the hole due to the diameter. Our drawings specifically say that
> coring
> is not allowed. The girder is not subject to uplift at the anchorage point
> but does experience significant vibrations every ten seconds. Does anybody
> know of a way to drill a 6" diameter hole and still have a rough enough
> surface to ensure adequate bond between the mortar and the walls of the
> hole. The contractor is squawking at using epoxy.
> <<<<
> I would strongly suggest that you check with the manufacturer of the epoxy
> you are proposing to use.  It is my understanding that epoxy manufacturers
> recommend that you use hole not more than 1/4" larger than the size of the
> bolt when using epoxies.  The two concerns are 1) with all that  epoxy
> curing it will produce high temperatures in the epoxy that will impact its
> strength and 2) there will be excessive creep if the bolt is subject to
> continuious loads.
> The other option is to use cemtitious grout but even so the 6" dia hole is
> probably larger than needed.
> As far as whether a cored hole will produce a rough enough surface I would
> recommend that you check with the manufacturer of the product you
> specified.
> Mark Gilligan