Towers
The telecommunication and wireless communication industries use towers, poles and mounts as support structures for antennas, personal communication systems, commercial and amateur broadcasting, home television and cellular telephones. There are two basic types of towers: self-supporting and guyed. Self-supporting towers can be three- or four-sided steel-lattice pyramids or boxes or tubular monopoles. Guyed towers are a slender, steel structure supported by one or more levels of braided and stranded high-strength steel guy cables that anchor it to the ground. When selecting the proper tower type, it is important to consider how much land it will occupy, the soil type of the land and the overall height and weight of the finished installation.
Guyed towers have the compressive strength to support its own weight, but does not have the strength to stand unsupported, and requires guy lines to stay upright and resist lateral forces. Guy lines are usually spaced at equal angles around the structure’s base. Guyed towers require much more land than self-supporting towers. The guy lines are generally anchored to the ground at a distance from the base equal to approximately 80 percent of the tower’s height. Soil types need to be suitable for supporting foundations or for holding the guy anchors. There are three things to consider when calculating load requirements. First, is wind speed, sometimes referred to as wind load. This is the force the wind has on the tower and antennas. Second, is ice load, sometimes referred to as radial ice. This is the amount of ice in inches that is formed around each tower part. Third, is antenna loading, which covers anything added to the tower initially, and in the future, that will be exposed to wind.
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