HomeMy WebLinkAboutID1C057-S WM1878 - 1450 North_Fall Letter - Certified
Sabre Industries, Inc.
7101 Southbridge Drive
Sioux City, IA 51111
March 11, 2026
Shane Smith
SBA Network Services, Inc.
8051 Congress Ave.
Boca Raton, FL 33487
RE: 150’ Monopole for WM 1878 – 1450 North 2nd East, ID (26-4164-CJP)
Dear Mr. Smith,
Upon receipt of order, we propose to design and supply the above referenced
monopole for a Basic Wind Speed of 105 mph with no ice and 50 mph with
1/4” ice, Risk Category II, Exposure Category C and Topographic Category 1
in accordance with the Telecommunications Industry Association Standard
ANSI/TIA-222-H, “Structural Standard for Antenna Supporting Structures,
Antennas and Small Wind Turbine Support Structures”.
When designed according to this standard, the wind pressures and steel
strength capacities include several safety factors. Therefore, it is highly
unlikely that the monopole will fail structurally in a wind event where the
design wind speed is exceeded within the range of the built-in safety factors.
Should the wind speed increase beyond the capacity of the built-in safety
factors, to the point of failure of one or more structural elements, the most
likely location of the failure would be within the monopole shaft, above the
base plate. If the wind pressure profile is similar to that used to design the
monopole, the monopole will buckle at the location of the highest combined
stress ratio within the monopole shaft. This is likely to result in the portion of
the monopole above leaning over and remaining in a permanently deformed
condition. Please note that this letter only applies to the above-referenced
monopole designed and manufactured by Sabre Industries. This would
effectively result in a zero foot fall radius at ground level.
Sincerely,
Amy R. Herbst, P.E.
Senior Engineer