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RE: Tall signs

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50 mph is unlikely to meet any local code in theory, or reasonable wind storm 
in practice, whether you are referring to sustained wind or gusts. As wind 
pressure is proportional to the square of the wind speed and your minimum 
design wind is unlikely to be less than 90 mph (I do not know where your 
structure is located), your client should be left with either the choice of 
having the structure removed or strengthened. All your factors of safety for 
materials, design, etc. have been used up on your loads. You may find that 
your structure is even insufficient for temporary construction loading, which 
would allow for much smaller return periods on wind.

Regarding an earlier post, I would not wish to rely on failure of the canvas 
to reduce your loads without an actual test. There may be sufficient drag even 
from torn material to keep your loads beyond any safe level.

James Cohen, PE

From: 	Alex C. Nacionales
Sent: 	Friday, August 21, 1998 18:02
To: 	seaint(--nospam--at)
Subject: 	Tall signs

 Thank You for your comments.

The revised sign structure with canvas sign installed, can handle winds up
50 mph(80kph) .

 Do you have any data about sudden gusts that exceed the above wind speed?

Thanks again.