Wind Loading; General; Calculation Of Lateral Force - Motorola PTP 400 Series User Manual

12

Wind Loading

12.1 General

Antennas and electronic equipment mounted on towers or pole mounted on buildings will
subject the mounting structure to 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 PTP 400 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 . v
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 PTP 400 Series Bridge Unit at different wind speeds is
shown below:
Item
PTP 400 Series
Bridge - integrated
antenna
PTP 400 Series
Bridge
Connectorized
The equivalent table in metric units is:
Item
PTP 400 Series
Bridge - integrated
antenna
PTP 400 Series
Bridge
Connectorized
2
Largest
Surface Area
(sq ft)
1.36
1.00
–
Largest
Surface Area
2
(metres )
0.1300
0.0930
–
153
Lateral Force (pounds) at
wind speed (mph)
80 100 120
37 57 82
27 42 60
Lateral Force (kg) at
wind speed (meters/sec)
30 40 50
12 22 34
9 16 24
140 150
112 129
82 95
60 70
49 66
35 48