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Re: HILTI Anchor for anchoring Vessels[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>, seaint(--nospam--at)seaint.org
- Subject: Re: HILTI Anchor for anchoring Vessels
- From: Neil Moore <nma(--nospam--at)omsoft.com>
- Date: Fri, 17 Mar 2006 20:21:44 -0800
It's pretty much always been the way you describe. In fact, the California State agencies and maybe the City of Los Angeles may even lower some of the allowable values. One has to be careful in reading the ICC reports as well. I believe that both Hilti and Covert require special inspection which can also increase the cost of the installation. Our office pretty much considers the reports as the law as it is part of the CBC (still used here in California) and the IBC, and will not get emotionally attached to the project.
At 05:49 PM 3/17/2006, Padmanabhan Rajendran wrote:
Neil, too, brought my attention to the ICC Reports. Thanks to both of you as well as to others who shared their views.
I found something interesting about the ICC Report vis-a-vis HILTIs' published tables for HVA adhesive anchors. The allowable loads listed in ICC are smaller than what HILTI allows. In addition, the adjustment factors for edge distance and anchor spacing are also more conservative in ICC tables. Furthemore, the tension-shear interaction formula recommended by ICC will yield a larger number in comparison with what would be calculated from HILTI's. In essence, ICC's recommendation has conservatism built in at three stages of the calculation. I was told by HILTI representative that ICC, for whatever reason, typically, adopts a higher factor of safety (obviously!). I was also told that ICC does not conduct any test or study on its own. It, simply, takes the ultimate values provided by HILTI (HILTI runs its own test pr ogram) and comes up with allowable values!
HILTI did not make a final recommendation except to say that the engineer is bound by the directive of the controlling permitting agency, if any, or by the code dictated by the client. If the client does not care or, if permitting is not involved, the engineer is free to use whatever he takes fancy to! That was comforting!
I am positive that such anamolies may exist between any other ICC report and the corresponding vendor data. I thought this information will be useful for the list members.
- Go to the ICC website and download ESR-1702 for Covert Operations, Inc. products. DUC values are in Tables 15 through 19.
- Bill Cain, S.E.
- Berkeley CA
- -----Original Message-----
- From: Padmanabhan Rajendran <rakamaka(--nospam--at)yahoo.com>
- To: seaint(--nospam--at)seaint.org
- Sent: Fri, 17 Mar 2006 12:41:48 -0800 (PST)
- Subject: Re: HILTI Anchor for anchoring Vessels
- 1. I did not see any tables and charts to design Covert, Undercut anchor at their web site. Does it mean that I prescribe the loads and the Company designs on a case by case basis?
- 2. Hilti recommends tensioning epoxy anchors. So, what may be your objections to it?
- Harold Sprague <spraguehope(--nospam--at)hotmail.com> wrote:
- 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)seaint.org
- > 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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