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RE: coefficient of friction

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ASTM C1028 is a test of sliding of a Neolite heel on ceramic tile and
similar material.  This is the one the lawyers go to in slip and fall
accidents.

Bob Garner, S.E.

-----Original Message-----
From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
Sent: Thursday, September 29, 2005 10:33 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: coefficient of friction

I am not familiar with this test.

Regards,
Harold Sprague





>From: "S. Gordin" <mailbox(--nospam--at)sgeconsulting.com>
>Reply-To: <seaint(--nospam--at)seaint.org>
>To: <seaint(--nospam--at)seaint.org>
>Subject: coefficient of friction
>Date: Wed, 28 Sep 2005 15:43:35 -0700
>
>List,
>
>What would be a good reliable source of information on the static
>coefficient of friction for DF-L (wet, per ASTM C1028)?
>
>TIA
>
>Steve Gordin SE
>Irvine CA
>
>   ----- Original Message -----
>   From: Harold Sprague
>   To: seaint(--nospam--at)seaint.org
>   Sent: Wednesday, September 28, 2005 3:03 PM
>   Subject: RE: Twist off bolts (was:Bolt retightening)
>
>
>   Tom,
>   That is correct.  That is why the twist off manufacturers are
>conservative
>   in the torque it takes to twist off the bolt.  Another critical
factor
>is
>   the lubricant.  If you have a large complicated structure and the
steel
>is
>   erected and plumbed.  Then you take a couple of weeks off because of
the
>   rainstorms that blew through.  You need to pull a pretty good
sampling
>of
>   bolts, load them into the Skidmore and verify if you are getting the
>   tension.  If not, you need to pull the bolts and relubricate them.
If
>the
>   bolts have surface rust, you can be off on the tension by a factor
of 2.
>
>   That is why special inspection by a QUALIFIED inspector is
important. 
>You
>   can make it fool proof and require the DTI washers plus the DTI
bolts. 
>That
>   way you can see on each and every bolt if you have the proper
tension. 
>When
>   the washer squirts, you have the tension.  And you have the ease of
>   installation offered by the twist off bolts which use electric
wrenches
>and
>   are light and easy to operate.
>
>   I think it would be fun to take some engineers out on a site, and
have
>them
>   install bolts using the various techniques.  It is also entertaining
to
>   remove the lubricant from a few bolts and even have some with light
>surface
>   rust.  Then put them into the Skidmore and see how much tension you
are
>   getting.  Or you can keep your clothes clean and attend one of Bob
>Shaw's
>   highly educational presentations on bolt installation.
>
>   I have done both.  I am a slow learner due to too much suds sucking
as
>an
>   iron worker back in my bullet proof days of youth.
>
>   Regards,
>   Harold Sprague
>
>
>
>
>
>   >From: "Tom Skaggs" <tom.skaggs(--nospam--at)apawood.org>
>   >Reply-To: <seaint(--nospam--at)seaint.org>
>   >To: <seaint(--nospam--at)seaint.org>
>   >Subject: Twist off bolts (was:Bolt retightening)
>   >Date: Wed, 28 Sep 2005 14:06:16 -0700
>   >
>   >The problems with relating bolt tension with torque (i.e.
calibrated
>   >torque wrench) were well documented in this thread.  I also
understand
>   >DTIs are a direct measurement of bolt tension, but aren't the twist
off
>   >bolts just another torque based method and not measuring direct
>tension.
>   >I've briefly looked at the NUCOR website, perhaps I don't
understand
>the
>   >twist-off mechanism.  Please explain?
>   >
>   >Tom
>   >
>   >________________________________
>   >
>   >From: Michael Hemstad [mailto:mhemstad(--nospam--at)mbjeng.com]
>   >Sent: Wednesday, September 28, 2005 13:36
>   >To: seaint(--nospam--at)seaint.org
>   >Subject: Bolt retightening
>   >
>   >
>   >Kevin,
>   >
>   >I concur with Harold (I'm sure he's relieved to hear that).  One of
the
>   >huge and seldom-quoted advantages of twist-off bolts is that they
can
>be
>   >inspected with certainty, from the ground, with very little effort
on
>   >your part.  If the spline is twisted off, it's done.  Therefore it
is
>   >entirely feasible to inspect every bolt on a project.  It really
adds
>to
>   >everybody's peace of mind.  And, as Harold notes, it's also
probably
>the
>   >cheapest solution.
>   >
>   >I've never had to spec these bolts into a project, because they're
>   >universally used around here; but if I saw ironworkers using the
>   >old-style bolts and spud wrenches, I'd start asking a lot of
questions.
>   >
>   >Mike Hemstad, P.E.
>   >
>   >Meyer Borgman Johnson
>   >
>   >Minneapolis, MN
>   >
>  
>
>-----------------------------------------------------------------------
-
>   >--
>   >
>   >From: "Harold Sprague" <spraguehope(--nospam--at)hotmail.com>
>   >
>   >To: seaint(--nospam--at)seaint.org
>   >
>   >Subject: RE: Bolt retightening
>   >
>   >Kevin,
>   >
>   >Torque wrenches are only supposed to be used in arbitration in the
>   >
>   >installation of A325 or A490 bolts according to the RCSC. Torque is
a
>   >very
>   >
>   >poor indicator of tension in a bolt. The tension is what you are
trying
>   >to
>   >
>   >achieve.
>   >
>   >Getting a Skidmore on the project site (hydraulic tension
indicating
>   >device)
>   >
>   >is not a big deal for most iron workers, and is fairly routine.
>   >
>   >Because of the variability, I would NEVER allow calibrated wrench
bolt
>   >
>   >tightening.
>   >
>   >When you boil it all down, the best and probably cheapest solution
is
>to
>   >
>   >replace all of the bolts with the tension indicating bolts using
the
>   >
>   >splines. The installation wrench rotates the nut while holding the
>bolt.
>   >
>   >The spline snaps off when the appropriate tension is achieved. You
>still
>   >
>   >have to install the bolts to "snug tight" with the faying surfaces
in
>   >full
>   >
>   >contact. And you still need the Skidmore on the site to verify the
>   >
>   >appropriate tension for the tightening procedure you select. The
>   >
>   >installation is a lot easier using the twist offs as opposed to
using a
>   >
>   >pneumatic wrench or a spud wrench with a cheater (for turn of the
nut).
>   >The
>   >
>   >labor is where you will save the money over other installation
methods.
>   >And
>   >
>   >the QC is better.
>   >
>   >If you want the ultimate in reliability, ease of installation, and
100%
>   >QC,
>   >
>   >use the DTI "Squirter" washers with "twist off" bolts. You get the
ease
>   >of
>   >
>   >installation with the "twist off" wrench and you get the tension
>   >indication
>   >
>   >that the "squirter" washers provide.
>   >
>   >If you decide to go against my incredibly sage advice and use turn
of
>   >the
>   >
>   >nut, use match marking with a paint stick. And never tighten bolts
>   >without
>   >
>   >a Skidmore.
>   >
>   >Regards,
>   >
>   >Harold Sprague
>   >
>   >
>   >
>   > >From: Kevin Below <kevinbelow(--nospam--at)videotron.ca>
>   >
>   > >Reply-To: <seaint(--nospam--at)seaint.org>
>   >
>   > >To: seaint(--nospam--at)seaint.org
>   >
>   > >Subject: Bolt retightening
>   >
>   > >Date: Mon, 26 Sep 2005 22:48:26 -0400
>   >
>   > >
>   >
>   > >I am in need of some guidance on the right technique for
retightening
>   >
>   > >bolts on a 40-year-old steel structure....
>   >
>   >
>   >
>
>   _________________________________________________________________
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