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Re: Period Calculation for One Story Building with Flexible Diaphragm, FE

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I agree, Frank, we're not going to do the subject calculations as though we
were fools. And it is clear that this technical question is being used
rhetorically, in a review process, to cast doubt on FEMA 310 in general.
Fine with me.  My stint as Lt(jg) CEC USNR concluded in charge of Seabees
maintaining a small Navy base along the banks of the Mekong River.
Mistrusting grandiose government programs took a great leap forward in those
years, and never slipped backwards.

You said,
> These authors [of FEMA 310] are recognized experts in the field of earthquake
>>engineering, particularly in the area of evaluation and retrofit of existing
>>buildings.

Right. But are they experts at buildings more than they are experts at
informing and guiding other people?   Often experts are absorbed in
inflicting elaborate, "expert" protocols on a situation and lose sight of
what the follower's purpose is and whether the follower can reliably get
realistic, practical results. 

Unclear text often results when technical experts meet and write general
protocols for others to follow --not to mindlessly follow, but with a blend
of the follower's own discretionary input. The writers will understand one
another, and their text language will be relatively faithful to the meaning
they're aware of, and they will be happy with it. But it will be garbled and
ambiguous to nearly everyone who hadn't attended and who missed out on the
oral commentary in the meeting. Like us.

Sometimes the text isn't faithful at all to the authors' consensus. That may
be the case here, where the lateral force for deflection purposes seems to
be a full 1.0 gravity acting sideways. 

And sometimes the text is carelessly set out so that it applies to a far
wider scope of situations than the authoring group ever considered or
intended, assuming they knew what they were doing with what they did
consider. That could explain inclusion of this deflection-based period
formula that is so uncertain as to how deflection is calculated.

The above comments are intended to help show that the review and correction
process such as you and others are doing is vital and indispensable. The
originators are accused here of no worse than acting as all humans do....
Provided, that is, that they answer all competent questions and critiques
fully and in good faith.   

Actually, it is a big mistake to entrust any product-originating body with
responsibility for the final version that's released for use. Some other
group that is expert at perfecting a prototype should take over. The
originating experts should by then be reduced to the role of technical
advocates who have no higher standing than peer review "test pilots" like you.  
  
Charles O. Greenlaw, SE   Sacramento CA

___________________________________
At 05:44 AM 6/14/98 EDT, you wrote:

 I am trying  to get the authors of FEMA 310 or the
>"mother of FEMA 310", which is FEMA 273, to explain how to calculate the roof
>diaphragm deflections used in equation (4-1).  I have contacted several of the
>Project Team members for ASCE FEMA 178 Update Project, the "father of FEMA
>310", asking them the same questions and am patiently waiting for their
>replies.
>   If I do not receive a reply from either the authors
>of FEMA 310 or FEMA 273 soon, it will influence how I respond in a peer review
>I am performing on the evaluation and retrofit of a real existing building,
>following these FEMA  Guidelines, because I will have to rely on my
>engineering judgment, hopefully not like a "fool."  I sincerely hope at least
>one of these authors takes the time to reply to my recent postings on the
>SEAOC List Server, because I consider the application of these FEMA Guidelines
>serious business and I would appreciate some answers soon.
>
>
>Frank E. McClure  FEMCCLURE(--nospam--at)aol.com