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Title: RE: ASD vs. LRFD
-----Original Message-----
From: Paul Meyer [mailto:PMeyer(--nospam--at)]
Sent: Tuesday, June 22, 1999 11:43 AM
To: 'seaint(--nospam--at)'
Subject: RE: ASD vs. LRFD

Similarly, anchors into concrete used to be designed based on the "bond strength" between the steel and the concrete, resulting in some very deep embedments of anchors.  Now we design based upon a "pull out cone" and the required embedments of anchors is much less.    For example, our corporate "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 a 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. 

It was "wrong" in that subsequent intelligence revealed that this was not the way these materials behaved in this configuration at all.

It is "wrong" to continue to use outmoded methods, period. You do yourself an injustice by not "upgrading" your knowledge and skill set, you do your employer or client an injustice by not putting forth the best effort you can. And you do your profession a great disservice by doing your part to keep it mired in the bygone era when an "engineer" was anyone who said he was an engineer, and had drawings to prove it.