[TowerTalk] Tower Questions

[Tower2sell@aol.com]

>The stanard tower analysis done  by this structual engineer is for Exposure B which is suburban terrian.  Some cities want Exposure C which is an open terrian where wind is unobstructed for a one mile radius.  
>

The ANSI/TIA/EIA-222-F, 1996 (the current code) does not have Exposure Factors. They have been eliminated and the equlivent of Exposure C used. Therefore You can no longer design for Exposure B - suburban terrian. Now keep in mind that some local juridictions do not use the EIA-222 like some counties in Florida. 

Another general comment is that the world is going from the fastest mile wind speed to the 3 second wind speed. The next version of the EIA (G) will change to the fastest mile. This means that the minimum basic wind speed (including gust factors) will be 90 mph instead of the current 70 mph. 

Tower2sell@aol.com

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