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RE: wind loads - Word Wrapping

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Please change the subject on threads which you are responding to where the
response has nothing to do with the subject or issue presented.
This will make it easier to search later if someone has a question regarding
"Word Wrapping" features in their email editor. As you have it, it is buried
in an unrelated post which makes it difficult to find in the thousands of
posts located in our archives.
Dennis Wish PE

|-----Original Message-----
|From: Bill Allen, S.E. [mailto:ballense(--nospam--at)]
|Sent: Saturday, March 07, 1998 6:15 AM
|To: seaoc(--nospam--at)
|Subject: Re: wind loads
|Word wrapping is a feature specific to your e-mail viewer. To find out
|how to turn on word wrapping in your software, look up "word wrap" under
|Bill Allen
|P. Rajendran wrote:
|> In some posts, such as this one, "word wrapping" is absent.  It
|> becomes
|> somewhat cumbersome to read the post.  Is there something I can do to
|> introduce "word wrap" in the document, or can something be done by the
|> author so that the document is contained within the screen width?
|> Rajendran
|> Harold Sprague wrote:
|> >
|> > Mark,
|> >
|> > Be careful to establish whether this is a "fastest mile" wind, a "3
|> second gust" wind, a "sustained wind", or a wind reported by the
|> weather service that has not been normalized.  It will make a very
|> large difference.  The ASCE 7-93 dealt with "fastest mile" winds as
|> does the UBC.  The ASCE 7-95 deals with "3 second gust" winds.  If it
|> is not normalized, call a wind engineering expert like CPP in Fort
|> Collins, CO.
|> >
|> > This being reported as a hurricane wind suggests a "one minute" wind
|> or "sustained" wind, which is the standard of hurricane guys.  They
|> will spout things like the Saffir-Simpson scale Category 5 which will
|> give a range of sustained winds.  If it is a sustained wind, convert
|> it to a 3 second gust using the Krayer-Marshall curve that is in the
|> appendix of ASCE 7-95.  Then use the ASCE 7-95 to determine the wind
|> pressures on your structure.  The conversion is not straight forward.
|> >
|> > If you chose to convert to a "fastest mile" wind to use ASEC 7-93,
|> be careful.  Using the curves becomes an iterative process in which
|> you close on a time of duration.  It takes about 3 or 4 iterations and
|> is not for the uninitiated.  You can reference Emil Simu's book on
|> wind design for good commentary and examples.  There is a paper
|> floating around that does not use the iterative technique.  It is
|> wrong.
|> >
|> > Also be careful in how you use the wind pressures.  You will
|> obviously use them to establish loads for your primary frame.  But
|> lateral drift for building performance is up to the engineer.  The
|> codes will not hold your hand on this one.  Currently the trend is to
|> use a 1 year wind for human perceptibility due to lateral acceleration
|> issues and a 10 year wind for deformation compatibility issues.  (Yes
|> deformation compatibility is an issue in other than seismic design.)
|> >
|> > Regards,
|> > Harold Sprague
|> > Krawinkler, Luth & Assoc.
|> > 4412 W. Eisenhower Blvd.
|> > Loveland, CO 80537
|> > Voice: 970 667-2426
|> > Fax: 970 667-2493
|> > Email: hsprague(--nospam--at)