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Re: High-strength bolts

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> > From:       SMEZSEZ(--nospam--at) [SMTP:SMEZSEZ(--nospam--at)]

> > A325-X bolts were specified to be installed at steel to column moment
> > resisting connection in an OMRF.  Instead, A325  friction type bolts
> > were installed, but were not torqued., but tightened well.  The bolts
> > are presently inaccessible.  Will the friction type bolts be accectable
> > without having to be torqued.

> From: "Sprague, Harold O." <SpragueHO(--nospam--at)>

> I always get nervous when engineers say torqued in lieu of tensioned, but
> that is another issue.  
> If the bolts were not tensioned, you do NOT have friction bolts.  

I always get nervous when engineers attibute assembly conditions to the
properties of the bolt ... friction bolt!?  ;-)

> for moment resisting connections.  Generally moment frames are made with
> slip critical (friction) connections.  You should be able to check the shop
> drawings to see if the threads will be in the shearing plane.  

This sounds like a moment end-plate connection. It is hard to imagine
that bolt shear is the controlling condition in the design (X vs SC
type). I can imagine some situations where fully tensioned bolts may not
be required in a moment connection but it would be too much work to
prove that. If the A325 bolts were supplied correctly (threads X-cluded)
then they are OK. It's unfortunate that the tensioning was not specified
on the drawings and there may be a claim by the contractor. So, just
torque'em down!

Paul Ransom, P. Eng.
Burlington, Ontario, Canada
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