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Re: Designing "Window Walls" per the 2003 IRC

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I think this came up a while ago (correlating 3 sec gust to news reports of "maximum sustained winds" used to classify a hurricane), maybe last spring.  I don't think I ever saw a definitive answer.   I guess it depends on how you do all of your factors.  The pressure equation is just the static force for a given airstream velocity. That I can deal with, along with the 3sec gust at 33ft above the ground in exposure C.  Factors for other exposures, topography, height above grade, geometry, the magical 0.75 "combined load" factor (even where wind is the only credible load), large volumes, gusts, directionality, duration (for wood), all muddy the water in what the "true" windspeed the structure can withstand.

Joe heard sustained winds of 120mph, I heard 110mph in New Orleans.  Further complicating the matter is that, as far as I know, sustained windspeeds in hurricanes are taken at altitude, not necessarily 33' above ground. I also assume they are doppler based and can be read at many altitudes, the maximum of which is used for classification. Katrina, I heard, topped 175mph while in the Gulf. 

I'm going to claim, in my face-to-face tirades, that mph are mph, and figure that I'm good to within ten or fifteen percent.  I won't mention the squared pressure relationship unless its to the benefit of the argument I'm making ;-)

Shawn M. Stambaugh, PE wrote:
Not to mention that ASCE is based on a 3 second gust, not sustained/fastest mile wind.  150 mph 3-second gust is only equivalent to about 130 mph fastest mile.  I'm not sure that much would survive a direct hit from a storm that strong as designed per current code (in FL anyways).

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