To: "INTERNET:seaint(--nospam--at)seaint.org" <seaint(--nospam--at)seaint.org>
Subject: RE: storage racks with partially restrained moment connections - wind frame analysis in high seismic zones
From: Peter Higgins <76573.2107(--nospam--at)compuserve.com>
Date: Tue, 20 Mar 2001 10:12:08 -0500
They should be nervous.
I'm not certain what you mean by 1997 RMI. That document was still pretty
rough. The "latest" RMI is quite a bit better. However, RMI inadvertently
legislated in other areas by including impact loads for all racks whether
machine loaded or not, need to make the impact regulations administerable,
and hopefully broaden the load scope of the standard to include types of
racks for which we currently have no guidance.
One of the reasons they will have great difficulty getting consensus for
ANSI is the lateral impact load. The deal struck between RMI, ICSC, SEAOC
and ICBO agreed that the RMI would become the rack design standard for IBC
2000 once adopted by ANSI. The ANSI adoption was critical, as they knew
that they would have some say in any future modifications. The two crucial
ones mentioned above are very important to both ends of the rack users
spectrum. The lateral impact load would destroy most retail shelving
systems which are hand loaded (a machine cannot even get in the aisle). The
impact protection issue is crucial to the "big box" retailers as it is so
nebulous that no one knows how to satisfy it.
Because of this, if RMI presses ahead, the consortium of users
(representing virtually all of the mass retailers in the country) will
submit a code change to take out the RMI, and replace with the 1997 UBC
regulations. A retrograde move, but at least they can live with it.
This is what consensus is all about. RMI has the best of intentions with
their changes, but they have no idea of the ramifications of some of them.
The consensus procedure is set up to avoid exactly this sort of thing. Its
a pain in the backside, but essential to writing good code. Ignore it, and
you often get nonsensical, unenforceable code.
Peter Higgins, SE
Message text written by INTERNET:seaint(--nospam--at)seaint.org
No fishing for me.
The NEHRP went forward with the 1997 RMI, but consensus codes are a bit
of an issue. The UBC and ASCE 7 also include non-consensus standards, but
the lack of ANSI accreditation makes them nervous. <