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Re: drilled and epoxied rods (Samir)

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In a message dated 03-01-29 20:51:39 EST, COEngineer(--nospam--at)aol.com writes:

<< Subj:     RE: drilled and epoxied rods (Samir)
 Date:  03-01-29 20:51:39 EST
 From:  COEngineer(--nospam--at)aol.com
 To:    seaint(--nospam--at)seaint.org, howard(--nospam--at)covertoperationsinc.com
 
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 This message is too long to be posted to this list.
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 There are several issues to look at when comparing values for adhesive 
anchors.  Listing or approval agencies (ICBO ES, LA City, etc) use different 
"safety factors" or methods of determining allowable capacities based on test 
results.  For example, ICBO ES AC 58 for adhesive anchors uses different 
safety factors depending on the results or non testing for seismic loading 
and/or long term creep.  
 LA City uses safety factors similar to ICBO, however the capacities can not 
exceed those listed in UBC Table 19E for embedded bolts.  So a 1" diameter 
anchor in 2000 psi concrete has a maximum allowable capacity of 5700 lb with 
inspection. The ultimate tested capacity of our CIA-Gel 7000 submitted to LA 
City is 49320 lb based on a 1 inch diameter and a 9 inch embedment, which 
means the safety factor in our LARR 25113 for that anchor is over 8 to 1!!!
 
 Other than that, with regard to catalog values, take a look a some of the 
other capacities in the report that you are using and see if the value seems 
reasonable.  You should not have to interpolate/extrapolate too far to get 
what you need, otherwise maybe you should be looking at a more complete 
approval.  Manufacturers that have gone through the extra expense of testing 
your specific application/size/material/etc should benefit from that testing 
by getting your spec.
 
 On another note, when looking at catalog values (or even ICBO report 
values), you should be wary of products that seem way higher in capacity that 
everyone else.  If you want to use these capacities, you should probably do 
some of your own investigation of what is going on.  The idea of an ICBO 
report, as mentioned by William Sherman below, is to try to evaluate products 
tested under consistent test parameters.  While ICBO AC 58 is a very thorough 
13 page document that has been under constant revision since ints inception 
(and we are now way ahead of where we started), there are still manufacturers 
that seek out its loopholes and exploit them.  
 For example, some manufacturers have engineered the concrete mix design so 
that while the compressive strength is low, say 2000 psi, the tensile 
capacities of the anchos in this concrete are very high.  This concrete meets 
AC 58 and is accepted by ICBO ES and an anchor report is published.  The 
manufacturer then goes on touting that their product is 30% stronger than the 
competition, when in reality it isn't.  If you call the ready mix company, 
pour the 2000 psi concrete that they give you, and test those high capacity 
anchors after the compressive strength is reached, what will you get?...30% 
lower values.
 This is a big issue with adhesive anchor manufacturers who are trying to 
decide which side of the coin to choose.  Pouring concrete that is not 
typically used in construction may not seem very honest, especially when the 
unsuspecting engineer has no idea.  Oh, but the lure of having higher 
capacities....  We could sure get a lot of specifications if everyone thought 
our product was stronger.  Unfortunately, the manufacturer that doesn't  do 
this testing may not only lose the engineers specification, but the approval 
when the submittal comes in from the contractor as well.  The engineer 
designed with that higher capacity, and the submitted product didn't use 
engineered mix designs, so they are rejected as being not good enough.
 
 Sorry for the rant, but this is an ongoing problem for companies who try to 
stick to the high road.  Not to mention the testing labs that don't pour that 
concrete.  Unfortunately, this has cost us an incredible amount of business 
in lost specs and rejected submittals.
 
 Best regards
 Howard Silverman
 Covert Operations
 
 In a message dated 1/29/2003 6:32:10 PM Eastern Standard Time, Samir Ghosn 
<sghosn(--nospam--at)harris-assoc.com> writes:
 
 >Dave
 >I am not aware of technical aspects or reasons for values being drastically
 >different.  May be some one who participate in this list can shed some
 >light.  
 >
 >Samir Y. Ghosn, P.E.
 >Harris & Associates
 >(800) 827-4901 xt 360
 >www.harris-assoc.com
 >
 >At 02:15 PM 1/29/2003 -0800, you wrote:
 >>Samir,
 >>
 >>I've seen some of the ICBO reports where the allowable values were
 >>adjusted by the LABC, but I'm not sure what the reason is for the
 >>sometimes drastic reductions.  Do you know of the history or technical
 >>aspect of these adjustments?
 >>
 >>Thanks,
 >>Dave K. Adams, S.E.
 >>Lane Engineers, Inc.
 >>979 N. Blackstone St.
 >>Tulare, CA 93274
 >>PH:  (559) 688-5263
 >>FAX: (559) 688-8893
 >>E-mail:  davea(--nospam--at)laneengineers.com
 >>
 >>
 >>
 >>-----Original Message-----
 >>From: Samir Ghosn [mailto:sghosn(--nospam--at)harris-assoc.com]
 >>Sent: Wednesday, January 29, 2003 12:47 PM
 >>To: seaint(--nospam--at)seaint.org
 >>Subject: RE: drilled and epoxied rods
 >>
 >>
 >>Be aware in the real world out there there are no ideal conditions that
 >>resemble test protocol.  Futher, if you look at ICBO approval reports
 >>and
 >>LABC approval reports you might find out that the established Catalog
 >>Values, Sales pitch program, are higher than approved reports allow.
 >>use
 >>some judgement.  Evaluate if the anchors are used to resist seismic
 >>conditions, evaluate if the test protocol allows for dynamic motion and
 >>relative degredation of the impacted bolt assembly.  Thats my 0.02
 >>cents.
 >>Good luck.
 >>  At 10:38 AM 1/29/2003 -0800, you wrote:
 >>>For those interested, I got a very good response from Hilti this
 >>morning.
 >>>Hilti uses a method called the 5% fractile to calculate their
 >>capacities.
 >>>With this method, 95% of the anchors tested exceed the listed capacity.
 >>In
 >>>addition a factor of safety is applied that varies from 3 to 5. Their
 >>manual
 >>>has some documentation on this. In my opinion, this seems adequate from
 >>a
 >>>practical standpoint. Their procedure has been accepted by ICBO in
 >>report
 >>>AC01 published January 2001. However, the testing of anchors to this
 >>>procedure has not been approved yet. I assume that this is in progress
 >>as
 >>>the method was only accepted recently. So for at least Hilti products
 >>it
 >>>sounds like this issue will be resolved in the future. I assume other
 >>>manufacturers will potentially use the same procedure to justify the
 >>values.
 >>>
 >>>
 >>>
 >>>-----Original Message-----
 >>>From: Sherman, William [mailto:ShermanWC(--nospam--at)cdm.com]
 >>>Sent: Wednesday, January 29, 2003 7:05 AM
 >>>To: 'seaint(--nospam--at)seaint.org'
 >>>Subject: RE: drilled and epoxied rods
 >>>
 >>>
 >>>I've struggled with the same question regarding which values to use. I
 >>often
 >>>use ICBO values for projects in California, since there seems to be
 >>more
 >>>emphasis on their use there; but I often use manufacturer's catalog
 >>values
 >>>for non-UBC areas. If I am comparing two manufacturer's values, such as
 >>for
 >>>product substitutions in submittals, I often use ICBO values for
 >>comparison
 >>>to ensure that consistent test parameters are used. 
 >>>
 >>>
 >>>William C. Sherman, PE
 >>>CDM, Denver, CO
 >>>Phone: 303-298-1311
 >>>Fax: 303-293-8236
 >>>email: shermanwc(--nospam--at)cdm.com
 >>>
 >>>
 >>>> -----Original Message-----
 >>>> From: Panos Trochalakis [mailto:panost(--nospam--at)ckcps.com]
 >>>> Sent: Tuesday, January 28, 2003 5:51 PM
 >>>> To: 'seaint(--nospam--at)seaint.org'
 >>>> Subject: drilled and epoxied rods
 >>>> 
 >>>> 
 >>>> I am working on a project that involves allot of drilled and 
 >>>> epoxied rods.
 >>>> Up until this point I have been using the capacities listed in the
 >>>> manufacturer's catalog. However, the allowable values in the 
 >>>> catalog do not
 >>>> match the allowable values listed in the ICBO report for the 
 >>>> same product.
 >>>> This appears to be consistent regardless of the manufacturer. 
 >>>> For example,
 >>>> both Hilti and Rawl do not match. In some cases the 
 >>>> discrepancy is large in
 >>>> others negligible. In other cases, anchor diameters listed in 
 >>>> the catalog
 >>>> are not even mentioned in the ICBO report. I called one 
 >>>> manufacturer and was
 >>>> told that they have conducted additional in-house testing to 
 >>>> create the
 >>>> allowables listed in their catalog. I am waiting to hear from another
 >>>> manufacturer but was hoping to get input from other engineers in the
 >>>> meantime. Do other engineers typically use the catalog values 
 >>>> and if so how
 >>>> do you feel about using values that are not backed up by independent
 >>>> testing?
 >>>> 
 >>>> Thanks in advance for any help.
 >>>> 
 >>>> 
 >>>> ******* ****** ******* ******** ******* ******* ******* ***

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