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Re: Residential Flexible/Rigid Diaphragm Analysis

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I really appreciate the way you express your point of view.

The structural engineering profession benefits greatly from your insight
and ability to articulate it.

Thanks for taking the time to respond.

Brad Friederichs
VE Solutions, Inc.
Sacramento, CA

At 02:17 AM 3/25/99 -0800, you wrote:
>Responding to Dennis Wish's recent solicitations:
>Dennis, if you are gleaning prior postings for an Online article, I
>submitted quite a bit on the diaphragm rigidity issue in 1998 on Aug 29 and
>Nov 18 and 21.
>I still think the code's demand that we regard diaphragms as conforming in
>reality to the extremes that human-invented figures of speech suggest
>("rigid" and "flexible") is the dumbest thing since when young ladies were
>similarly divided into two distinct categories. You remember, there were
>"good girls" and "bad girls". And nothing else. The first kind were good for
>marrying and bearing your children. The second kind were good for other
>purposes we need not specify here. 
>Like with this spurious code expectation that we can tell the difference in
>diaphragms and rely on the result, telling the difference between good and
>bad girls hasn't been all that certain. My great-grandfather F.B.Ogden in
>Oakland wouldn't let his daughters wear any red clothing, because it was
>"the sign of the fallen woman". His judgment seems quaint now, but the
>voters back then kept re-electing him as a superior court judge.   
>In my own youth, the girls themselves, when it came to being good or bad,
>seemed to sort out behaviorally as "rigid" or "flexible", so to speak.
>Performance-based evaluation, we might proudly call it now.
>But back then, the girl classifications were just for guideline purposes.
>You didn't get sued or lose your license and retirement savings if you
>mistook one kind of girl for the other and made a poor choice. But with the
>building code, mistaking rigid for flexible is disastrous as soon as an
>adversary's expert opines you got it wrong. The fact that the building
>itself didn't care is only a curiosity. You are into an expensive defense
>for violating a regulation intended to protect people from injury. Serious
>So how did this pitfall come to be inflicted on us? I suggest looking to
>Mark Gilligan's posting on 2-27-99, the pertinent part of which is:
>>I have observed that a number of code provisions have been adopted with
>>little technical data backing them up.  The SEAOC Seismology committee has
>>generally done a good job but ultimately the individuals find themselves
>>having to make decisions on subjects that they have not seriously
>>researched.  In this context people use their  best judgement.  I believe
>>that the provisions on redundancy probably fell in this catagory. The
>>problem is that what may seem rational occasionally isn't.
>I discussed Mark's implication in early March at a SEAOC dinner meeting with
>another regular code formulation participant, who is with a state agency
>keenly concerned with seismic codes. He confirmed that code language very
>often comes from one person on a committee, usually an energetic and
>forceful advocate, and gets approved with little or no validation in depth.
>Usually voting committee members shoot from the hip on little knowledgeable
>debate, because the agenda is too full, and was distributed too close to the
>meeting date to absorb and find flaws in. And the plane home leaves too
>soon. This is what my own experiences confirm. On the few issues I can get
>up to speed on and find big defects in, it is still hard at the meeting to
>get an edge in wordwise. I have in past writings referred to these
>committees as "empires" and been told that is an understatement.
>I do better at Board of Registration meetings. I have spoken on enforcement
>issues and pointed out an anomaly:   The Board disciplines individual
>engineers for failure to fulfill the duty of due care, such as mistakenly
>making a code violation, on a single element of a single building. But the
>code provision itself was originated with less care than taken by the
>offending engineer in its use. And the code doesn't just affect that one
>building, it affects all buidings. With less care taken. How do you Board of
>Registration members want to discipline that??  Blank stares follow; no
>complaints were received so they have no idea. But why should the struggling
>code users suffer the burdens? Why not the code originators? The stories of
>code formulation proceedings are plainly stories of failure to render due 
>Questioning "authority" itself, not the orders disseminated by authority, is
>where this subject's inquiry should head.
>Charles O. Greenlaw, SE    Sacramento CA
>Vietnam Vet who hasn't forgotten what can happen