When the slip-critical bolts slip, which they may since they were not
properly pretensioned, they will go into bearing, and behave as either
A325-N or A325-X. The question is - does the length of the bolts installed
keep the threads out of the shear plane (A325-X)?
If the contractor designed the connection as slip-critical, it should also
work even in the shear-bearing condition, even with threads in the shear
plane. All this assumes they did nothing special to the faying surface, like
use a Class B coating, to use fewer bolts.
By the way, most current practice calls for bolts in moment connections to
be slip-critical, not bearing type.
Steel Structures Technology Center
From: SMEZSEZ(--nospam--at)aol.com [mailto:SMEZSEZ(--nospam--at)aol.com]
Sent: Friday, April 21, 2000 4:59 PM
Subject: High-strength bolts
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.