[TowerTalk] Tower concerns

[K7LXC@aol.com (K7LXC@aol.com)]

In a message dated 1/15/01 10:02:26 AM Pacific Standard Time, aa4lr@arrl.net 
writes:

> Do you want to do it "right" or "good enough"? Your source is correct 
>  that Rohn tower sections are actually stronger than their published 
>  figures. The design rules are likely to be 200-300% over the rated loads. 

    I don't think that's right. The figures I've seen are 30-50%. The problem 
is that wind pressures do not go up linearly - the pressures go up 
geometrically. You run out of engineering overhead real quick if your tower 
takes a gust higher than your design windspeed. For instance, a wind 71 MPH 
exerts windpressure of 20 PSF; a gust at 87 MPH has a force of 30 PSF - a 50% 
increase for a 16 MPH increase in windspeed. 

    The LXC Prime Directive still applies - DO what the manufacturer says.

Cheers,   Steve   K7LXC
Tower Tech

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