Hank Lonberg wrote the following to me:
>Remember your statement only applies to situations where the design wind
load is 75 mph (3-sec gust) and exposure "C" per the IBC. The
>most common required design wind criteria is 80 or 85 mph and exposure "B".
I am curious if the wind forces on your were
>tower calculated using the IBC wind criteria (usually ASCE-7 procedure) or
were they done using the TIA-222-G?
> My experience is that you can get an bit higher allowable antenna area for
a HDX-572 if one used the TIA-222-G which
>is reference as an allowable design procedure for communication towers in
the IBC 2006 or the new 2009 edition.
I reviewed the pages of the analysis which described the application of the
code. I need to revise my earlier post to the following:
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The analysis done for me was for a 90 mph (3 sec gust), which is a 76 mph
fastest mile with exposure C.
US Tower used TIA-222-F and not TIA-222-G which apparently is not yet a
requirement for Idaho. At my request they provided both the 'B' and 'C'
exposure results.
The exposure C limit was 11.0 square feet for round members; the exposure B
limit was 14.1 square feet for round members. Both values are for antennas
at 73 feet above ground.
Tod, KØTO
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