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Re: HILTI Anchor for anchoring Vessels

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If you are trying to stay with HILTI note that they have a self drilling mechanical undercut anchor called the HILTI HDA and comes in two styles; one as a pre-set type and the other as a through-set type.  Call them or look up their catelog on the net.

Thomas Hunt, S.E.

"Harold Sprague" <spraguehope(--nospam--at)>
03/17/2006 11:16 AM
Please respond to seaint
Re: HILTI Anchor for anchoring Vessels

I have used a Covert "Ductile Undercut Anchor" post installed mechanical
anchor rod and tensioned the anchor rods after installation.
On the applications that I have employed, the bolts were checked after a
week and showed no relaxation.

I would advise against tensioning an epoxy anchor.

Harold Sprague

>   ----- Original Message -----
>   From: Padmanabhan Rajendran
>   To: seaint(--nospam--at)
>   Sent: Friday, March 17, 2006 6:58 AM
>   Subject: HILTI Anchor for anchoring Vessels
>   A client wants to set a vessel (8' dia X about 55' tall) on an existing,
>2' thick, concrete mat, and anchor the vessel to the mat with 1" dia HILTI
>epoxy grouted anchor rods. The tension and shear in the bolt is 11000 lbs
>and 1000 lbs respectively. My scope of work is to determine the bolt
>embedment depth. I understand that the bolt will be pretensioned after the
>vessel is installed.
>   I used the published values of nominal bolt loads, adjustment factors
>for edge distance and bolt spacing etc. to calculate the bolt embedment
>depth.  One of the standard embedment lengths (12.375") is sufficient to
>support the vessel.
>   What bothers me is that the post-installed epoxy anchors are not
>approved by ACI 318 (See Appendix D for Scope of application) mainly
>because the reliability of these type of anchors has not been certified in
>accordance with ACI 355.2. However, the published bolt values in HILTI
>catalog have been certified, by  ICC Evaluation Service, to conform to UBC
>1997, and 2000 IBC. The certification stipulates that it is valid only when
>the concrete is uncracked. The restriction stems from the fact that the
>anchors were not tested in cracked concrete environment.
>   The current thinking in anchor bolt design is that the headed bolt, or
>something similar, is the most effective anchor element. It is reported
>that L- shaped and J-shaped bolt perform poorly, in comparison. If L-shaped
>and J-shaped bolts perform poorly, how can a straight piece (despite having
>threads) perform any better?
>   Is it possible to pretension an, un-sleeved, anchor bolt? Is it not
>likely that concrete near the surface will crack?
>   Please share your thoughts and experiences, if any.
>   Thanks.
>   Rajendran
>   Relax. Yahoo! Mail virus scanning helps detect nasty viruses!

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