User Manual

Wind Loading
143
12 Wind Loading
12.1 General
Antennas and electronic equipment mounted on towers or pole mounted on buildings will subject
the mounting structure to significant lateral forces when there is appreciable wind. Antennas are
normally specified by the amount of force (in pounds) for specific wind strengths.
The magnitude of the force depends on both the wind strength and size of the antenna.
12.2 Calculation of Lateral Force
The 500 Series bridge with or without the integral antenna is essentially a flat structure and so
the magnitude of the lateral force can be estimated from:
Force (in pounds) = 0.0042 . A . v2
Where A is the surface area in square feet and v is the wind speed in miles per hour.
The lateral force produced by a single 500 Series bridge (integrated or connectorized model) at
different wind speeds is shown in Table 18 and Table 19.
Largest Surface Area (sq
ft)
Lateral Force (Pound)
at wind speed (mph)
80 100 120 160 200
PTP 500 Series Bridge -
Integrated
1.36 27 41 57 101 164
PTP 500 Series Bridge -
Connectorized
1.00 27 42 60 98 N/A
Table 18 Lateral Force – Imperial
Largest Surface Area (sq m) Lateral Force (Kg)
at wind speed
(m/s)
30 40 50 60 70
PTP 500 Series Bridge - Integrated 0.130 12 22 34 49 66
PTP 500 Series Bridge -
Connectorized
0.093 9 16 24 35 48
Table 19 Lateral Force – Metric