To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject: RE: ASD vs. LRFD
From: Robert Rollo <rrollo(--nospam--at)TEAM-PSC.com>
Date: Tue, 22 Jun 1999 13:19:13 -0500
AISC "guide for design of baseplates" cautions about the use of the
washer. It actually can decrease the resistance of your anchorage.
not sure what the implications of the 1923 section would be with the
washer . . . ?
> > From: Paul Meyer [SMTP:PMeyer@HASimons.
> > Similarly, anchors into concrete used to be designed based on the "bond
> > strength" between the steel and the concrete, resulting in some very
> > embedments of anchors. Now we design based upon a "pull out cone" and
> > required embedments of anchors is much less. For example, our
> > "standard" for 25 mm (one inch) anchors has gone from 600 mm (24 inches)
> > embedment for a hooked anchor to 250 mm (10 inches) for an anchor with
> > nut and washer on the bottom.
> > This doesn't mean that the old method was "wrong" in that it caused
> > failures, but it was "wrong" in that it resulted in wasting material and
> > was based upon an incorrect understanding of what kept the anchor in the
> > concrete.
> > > Isn't it somewhat irresponsible to call a design method
> > > "wrong" when the
> > > method was accepted and used for over 4 decades by all
> > > structural engineers
> > > on the continent of North America and was never questioned as to its
> > > correctness and engineering validity ???
> > See my comment about the method used to design two-way slabs 80 years
> > Was it "accepted"? Yes.
> > Did it "work"? Yes.
> > Was it "wrong"? Yes.