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Re: Anchor Embedment Inspection

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At 12:57 PM 9/16/98 -0700, you wrote:
>I have a question, particularly for any special inspectors on the list.  For
>expansion bolts we have always specified minimum embedment length on our
>drawings and schedules.  In Hilti's Product Technical Guide (And I assume on
>others) the required hole depth is greater than the embedment by one bolt
>diameter.  This is due to the fact that the load is transferred at the wedge
>not at the bottom of the bolt.  My questions to the inspectors are this:
>1) When you are checking depth of holes are you checking against minimum
>embedment or are you checking for the minimum hole depth (which will always
>be deeper for expansion bolts).

Pursuant to the ICBOES Research Reports installation procedures, the
Special Inspector should be aware of the difference in the initial
embedment and the final, torqued embedment.  However there is only one
agency, the City of LA, whose licensing procedure for Deputy Inspectors
(also known as Special Inspectors) includes an additional examination
specifically for the installation of Drilled-in Anchors and only with the
successful completion of this examination is an Inspector deemed qualified
to inspect a Drilled-in Anchor.  There are many different varieties of this
anchor, be it epoxy, undercut, back cut, shell, deformation, wedge and more
and you as an Engineer should be aware of the qualifications required.  One
simple way is to specify an accredited Inspection Agency for assurance that
the quality of the inspection is what you'd expect.  Chapter 17 of the UBC
has mandated for several code cycles that the Engineer of Record "specify
the name of the individual or firms that will performing the inspections
and what they will be inspecting".

>2) Does it create problems in the field when the plans list only embedment
>and not minimum hole depth?  Which would you like to see specified on the
>plans? (Both??) As a design engineer I am very rarely on the job during
>installations.  We depend on the special inspector for these verifications
>in critical applications.  My feeling is that we will need to be more
>specific on our drawings and schedules so it is very clear that we are
>getting the embedment we need.

It certainly couldn't hurt to spell it.  Especially if yu aren't familiar
with the Inspection Agency.  And don't confuse Test Labs and Inspection
Agencies.  Certification as a Test Lab does NOT mean accreditation as an
Inspection Agency.  They are two different issues and although a Test Lab
can also be accredited as an Inspection Agency, only one in Southern
California has sought and achieved that status, so you should be really
particular with your Inspection Program.  A copy of an Inspection Program
that exceeds the minimum requirements of the UBC can be found through my
web site, if you're interested.

Still plugging,

sandyp(--nospam--at) 	 (800)598-1970    Fax(310)376-5294	 Hermosa, Redondo and Carson, CA
Live your life as an exclamation, not an explanation.