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Re: Diaphragm and wall deflections

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In a message dated 98-03-03 05:12:01 EST, cgreenlaw(--nospam--at)speedlink.com write:

>  During SEAOC Seismology Committee deliberations leading
>  up to the 88 UBC version, masonry guru Jim Amrhein told me he felt 0.005 
>  way too stringent for drift of masonry walls. I recall hearing 0.020 spoken
of
>  approvingly.  

Charles,
You either have an elephantine memory or extensives files and a great info
retrieval system.   I had long forgotten this information until you mentioned
it.   I was chairman of the ICBO Seismology Code Development Committee in 1986
when the massive SEAOC code change package was processed.  After reading your
comment above, I now recall Jim Amrhein sounding me out on how I would react
to a floor motion at the annual meeting to relax the.005 limit.  As you may
know, during the annual meetings, the various committee chairs sit up on the
podium to serve as resources for questions that may come up on what transpired
at the code change committee sessions.  A frequent question is whether a
specific point or issue had been discussed at those sessions, because no new
material or issue may be introduced from the floor at the annual meetings.  On
the issue of the .005 limit, Jim had briefly stated his opinion at the code
change sessions.  However, I didn't consider there had been sufficient
discussion of the issue such that  I could recommend to the moderator to allow
a motion from the floor, and Jim never offered it.

Now that my memory about that ICBO annual meeting has been jogged, I recall an
amusing incident during the backroom negotiations between numerous challengers
to the SEAOC package.  A bit of background information:  At the annual
meetings, it is unwise for opposing factions to engage in contentious debates
over technical issues.  When that happens, the voting building official
audience often becomes confused, then bored, and finally annoyed if a debate
drags on.  When that happens, they tend to vote down everything related to
that issue or challenge.  Thus, it's in the best interests of opposing
factions to meet beforehand and come to compromises if possible.  When a
concensus position is presented, it usually sails through. 

A large number of the challenges to the SEAOC package were over the seismic
zone map.  SEAOC had taken a position that it had the knowledge to do a
credible job within California, but that for other states, it would act only
as a 'draftsman' to produce a map that reflected the input of credible
groups/organizations with knowledge of those other areas.  Not surprisingly,
the map in the package as originally submitted contained anomalies and
discontinuities at statelines.  Many of the challenges were from folks who
felt their area was inappropriately zoned.  Their convictions somehow had to
be reconciled with the need to produce zone boundaries that were more
'natural' in shape than state boundaries.

So, the various challengers gathered in my hotel room on the night before the
challenges were to be debated on the floor, and in a marathon session, managed
to hammer out a compromise that mollified as many folks as possible.  Ed
Zacher was wielding the french curve and changing the boundaries as each
agreement was reached on a specific portion of the map.  At some point during
the meeting, in an attempt to relieve some of the tension in the air, someone
(most likely from California) drew an amoeba-shaped polygon around the
Buffalo, NY area, and labeled it as Zone 4.  At the time, many West Coast
engineers and academics were still in shock over the recent decision of FEMA
to establish the National Center for Earthquake Engineering Research in
Buffalo instead of at Berkeley or in So. Calif.  The polygon was to poke fun
at Buffalo, of course, and everyone had a good laugh.  Unfortunately, nobody
bothered to erase it when the meeting was over.  This oversight wasn't noticed
until the next day, when copies of the newly revised map were being
distributed to the voting membership for consideration!     Only hurried
erasures and redistributions of the map kept Buffalo out of Zone 4 in the 1988
edition of the UBC.  And that's" the rest of the story" on how code changes
occasionally may be more, or less, than what gets printed.   :-)

Frank Lew, SE
Orinda, CA