Structural Standards for Towers - TIA/EIA Wind Speed County Listing

[adurbin]

I'm using the TIA/EIA structural standard for steel antenna towers and antenna supporting structures. My question is in regards to determining the basic wind speed. I'm analyzing a monopole tower and the site is in Newport News, VA. Which is also the name of the county (Newport News) However, when looking up the applicable basic wind speed Newport News county is not listed. It seems as though the code is treating it as a city area not a county. What basic wind speed should be used in the analysis? The nearest county, other..?? Thanks for the help

 

[amokhta]

Note 3 at the end of the Table in Section 16 reads: " For locations not designated as a county, use basic wind spped for the closest county to the site."

 

[adurbin]

Thanks I also found some useful information by emailing TIA.

The Newport News uniform building code says:

"Local Design Data:Wind Speed 90 MPH Continuos (BOCA); 110 MPH 3 Second Burst (ASCE-7)"

http://www.newport-news.va.us/codes/nncode.htm

 

[mfaris]

Newport News is a city. There is no "county" of Newport News" in Virginia.

(look up a full list at the NaCO website)

 

[Polecat]

Since EIA 222-F uses fastest mile wind speed measurement (based on Exposure C), you can take the ASCE 7-98 basic wind (3-sec gust) and convert it to FM. The difference is approximately 20%. The data and link that Adurbin provided you will just about answer all your questions.

Be sure and check to see whether the structure is within 1500 ft of the shoreline or not. If so, then, you would need to upgrade to Exposure D. Also, don't forget the 1/2" of ice!

http://www.spiraleng.com