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RE: Outstanding issues

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Regarding diaphragms and shear walls, I've found the book "Design for
Lateral Forces" by Ambrose and Vergun to provide a good description of these
elements and their design. It does include an example of a shear wall with
door openings using tabulated relative stiffnesses (Fig. 6.26);
unfortunately it does not seem to have an example of a horizontal diaphragm
with a web opening, although on pages 31-32 it does briefly talk about
design of web openings in diaphragms. 

Regarding "dispersion" in development of response spectra, in a geotechnical
report I received for a past project it stated "The choice of whether to use
the mean or the mean-plus-dispersion value is up to the designer who
ultimately decides the factors of safety to be applied to the design." It is
mainly a question of uncertainty and risk. If you use the mean value, there
is a greater chance that it will be exceeded than if you use the
mean-plus-dispersion value. (For my project, the mean-plus-dispersion value
was about 30 percent higher than the mean value. I'm not sure, but I think
this may be the same as "mean-plus-one standard deviation?) If you scale
your results down to code values, this is probably a moot point, but if you
want to design above and beyond the code forces, this is one way to reduce

> -----Original Message-----
> From: Attila Beres [mailto:Attila.Beres(--nospam--at)]
> Sent: Tuesday, June 13, 2000 10:49 AM
> To: Seaint Listserver posting
> Subject: Outstanding issues
> I have posted the following questions a couple of weeks ago 
> and have not received answeres. Let's try it one more time:
> 1. Would somebody please recommend a good reference (maybe 
> with numerical examples) for the analysis of rigid diaphragms 
> with openings. I am primarily interested in concrete and 
> composite decks with big holes, but also in concrete shear 
> walls with door openings (I have the book by Paulay and Priestley).
> 2. I have heard various rumors to what extent SE exam-takers 
> supposed to reference the code sections/equations. Would you 
> please clarify?
> 3. Could someone please explain the rational  for the use or 
> not-use of dispersion in the development of Response Spectra, 
> as it relates to the design of new or evaluation of existing 
> structures.