Post-installed anchors

From what I have learned over the past 5 years using the Appendix D - formerly in another document, the values from Hilti, Simpson, Etc. cannot be compared directly. I have always used the manufacturer test values if available. I know Simpson and I think Hilti have a couple of anchors that can be used in cracked concrete.

When using Appendix D, you have to use the coefficients that the manufacturers give you, but there aren't too many anchors out there that fall into this category.

I use Appendix D, for anchor bolts and headed studs. I use the manufacturer catalogs/programs for the others.

From a presentation I attended last month, Simpson, and I assume Hilti, are preparing new editions of their product reports for use with ACI 318-05.

With the Appendix D design model, you must consider cracked concrete in most cases. As such, only a few post installed anchors are acceptable for use.

Simpson has seminars to help explain (the guy in GA really does provide a non biased technical presentation), ACI has seminars and so on. It really does seem to be a big step from what has been the status quo.

Expect some changes.

Good luck!

Daniel

For manufactured post-installed anchors, I use the test report values that is adopted by the jurisdiction. Traditionally, the code shear and tensile capacities for embedded anchors were much smaller than the test report allowable values for post-installed anchors with comparable diameter and embedment. Though I haven't used Appendix D enough to get the "feel", I anticipate similar.

I agree with rgerk to use Appendix D for embedded bolts and test report values for proprietary post installed anchors (expansion anchor, adhesive anchor, shot-pin, screw anchor, etc).

Be aware that if you use ICC reports (ICBO reports) for manufactures values, as of January 1st of 2007, all ICC reports for mechanical anchors that are not approved for the new criteria of ACI 318 App. D have been canceled and deleted. Check for each mfg. to see what products they may have that are still approved for structural use, products that are advertised as being approved for cracked concrete may not be. I would disagree that the new methods of App. D have lower values for post installed anchors than the old ASD mfg. data. However, the new testing criteria is much more stringent and lesser quality products may indeed have lower values than previously tested.

Am I the only one who notices a huge difference in anchor embeddment requirements when comparing an epoxy anchor to a cast-in anchor. We've had a recent project where the contractor wanted to change from a 1 1/4" epoxy anchor (power-fast by powers) with 15" embed to a cast in anchor. I calculated that they'd need to replace it with a 1 1/4" J-bolt with a 32" embeddment. Not sure if Appendix D is just more conservative or if epoxy anchors are just that much stronger.

J-bolts now have much less tension load compared to headed studs or a rod with a nut on the end. Recalculate with a headed stud using App. D and your answer will be much more reasonable. I would estimate that J bolts are about 1/4 of the tensile load of a headed stud using the new calculation method.

Are J-bolts really as poor as the formulas suggest?

I used Euro standards. There's one annex dedicated to post-installed anchors. I.e. ETAG Annex B. Hilti has published capacities according to the test procedures given by the EOTA - European Organization for Technical Approvals.

In Profis also, there's one option is to design using ETAG.

for a 1-1/4 anchorbolt, a 20" headed bolt should develop the capacity of the bolt...

Dik

The story goes like this straight from the mouths of the fastener manufactures and the guys as ACI.

To use the proprietary post-installed fasteners such as Hilti or Simpson, the post-installed fasteners have to be qualified under a testing procedure which is stated in ACI 318 Appendix D. There were problems with the original testing procedure in ACI 318-02. None of the manufacturers tested any on their products because they did not want to waste their time and money, therefore none of their porducts were qualified to use in ACI 318-02. ACI has since revised the testing procedures for post-installed anchors and anchor manufacuturers have started testing their anchors to qualify them for use in ACI 318-05. The manufacturer has to test the anchors and submit design information for the anchors. As of today, Hilti has several anchor qualified for Appendix D and Simpson has a couple. I am unaware of any others. The new Hilti 2006 catalog has the design values for use in ACI 318-05 Appendix D for their anchor which are qualified. Contact Hilti or Simpson representatives. I have a good relation with the Hilti rep in Pittsburgh and he is very helpful. I have an entire design binder from them.

If the anchors are not qualified, you cannot use Appendix D. You have to use the proprietary design information from their catalogs.

The Hilti software is called PROFIS, a free download from Hilti. Simpson has a new free downloadable product which they say conforms to App D, however, their proprietary products such as "strong bolt" are the only ones you can use with their programs.

It will take some time before the post-installed anchor companies get all the kinks worked out. I personally think App D is highly flawed especially with regard to allowable shear. App D was rushed into publication without thought to the unintended consequences and is really a "work in progress." I expect to big revisions to App D over time.

For anchors under seismic or wind loading, I use App D and only specify headed bolts.