A TOWER is a tall structure , taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures.
Towers are specifically distinguished from "buildings " in that they are not built to be habitable but to serve other functions. The principal function is the use of their height to enable various functions to be achieved including: visibility of other features attached to the tower such clock towers ; as part of a larger structure or device to increase the visibility of the surroundings for defensive purposes as in a fortified building such as a castle ; or as a structure for observation for leisure purposes; or as a structure for telecommunication purposes.
Towers can be stand alone structures or be supported by adjacent buildings or can be a feature on top of a large structure or building.
* 1 Etymology * 2 History * 3 Mechanics
* 4 Functions
* 4.1 Strategic advantages * 4.2 Potential energy * 4.3 Communication enhancement * 4.4 Transportation support * 4.5 Other towers
* 5 Gallery
* 6 See also
* 6.1 General * 6.2 Towers in warfare
* 7 References * 8 Further reading
Old English torr is from Latin turris via Old French tor. The Latin term together with Greek τύρσις was loaned from a pre-Indo-European Mediterranean language, connected with the Illyrian toponym Βου-δοργίς. With the Lydian toponyms Τύρρα, Τύρσα, it has been connected with the ethnonym Τυρρήνιοι as well as with Tusci (from *Turs-ci), the Greek and Latin names for the Etruscans (Kretschmer Glotta 22, 110ff.)
Towers have been used by mankind since prehistoric times. The oldest
known may be the circular stone tower in walls of Neolithic Jericho
(8000 BC). Some of the earliest towers were ziggurats , which existed
Sumerian architecture since the 4th millennium BC. The most famous
ziggurats include the Sumerian
Some of the earliest surviving examples are the broch structures in
Other well known towers include the
Leaning Tower of Pisa
Up to a certain height, a tower can be made with the supporting structure with parallel sides. However, above a certain height, the compressive load of the material is exceeded and the tower will fail. This can be avoided if the tower's support structure tapers up the building.
A second limit is that of buckling—the structure requires sufficient stiffness to avoid breaking under the loads it faces, especially those due to winds. Many very tall towers have their support structures at the periphery of the building, which greatly increases the overall stiffness.
A third limit is dynamic; a tower is subject to varying winds, vortex shedding, seismic disturbances etc. These are often dealt with through a combination of simple strength and stiffness, as well as in some cases tuned mass dampers to damp out movements. Varying or tapering the outer aspect of the tower with height avoids vibrations due to vortex shedding occurring along the entire building simultaneously.
Although not correctly called towers many modern skyscraper are often
called towers (whereas they are classified as 'buildings'). In the
The tower throughout history has provided its users with an advantage in surveying defensive positions and obtaining a better view of the surrounding areas, including battlefields. They were constructed on defensive walls , or rolled near a target (see siege tower ). Today, strategic-use towers are still used at prisons, military camps, and defensive perimeters.
By using gravity to move objects or substances downward, a tower can be used to store items or liquids like a storage silo or a water tower , or aim an object into the earth such as a drilling tower . Ski-jump ramps use the same idea, and in the absence of a natural mountain slope or hill, can be human-made.
In history, simple towers like lighthouses , bell towers , clock
towers , signal towers and minarets were used to communicate
information over greater distances. In more recent years, radio masts
and cell phone towers facilitate communication by expanding the range
of the transmitter. The
Towers can also be used to support bridges, and can reach heights that rival some of the tallest buildings above-water. Their use is most prevalent in suspension bridges and cable-stayed bridges . The use of the pylon, a simple tower structure, has also helped to build railroad bridges, mass-transit systems, and harbors.
Control towers are used to give visibility to help direct aviation traffic.
* To access tall or high objects: launch tower , service tower ,
service structure , scaffold , tower crane , tower wagon
* To access atmospheric conditions aloft: wind turbine ,
meteorological measurement tower , tower telescope , solar power
* To lift high tension cables for electrical power distribution
* To take advantage of the temperature gradient inherent in a height
differential: cooling tower
* To expel and disperse potentially harmful gases and particulates
into the atmosphere: chimney
* To protect from exposure:
BREN Tower , lightning rod tower
* For industrial production: shot tower
* For surveying: Survey tower
* To drop objects:
Drop tube (drop tower), bomb tower , diving
* To test height-intensive applications: elevator test tower
* To improve structural integrity: thyristor tower
* To mimic towers or provide height for training purposes: fire
tower , parachute tower
* As art:
* For recreation: rock climbing tower
* As a symbol:
Tower of Babel
The term "tower" is also sometimes used to refer to firefighting equipment with an extremely tall ladder designed for use in firefighting/rescue operations involving high-rise buildings.
Polish pavilion at the New York World's Fair, USA 1939
Russian TV tower in Penza
Remains of a medieval watchtower, ancient city wall of
Typical towers at Dartlo, Tusheti
Towers form Ingushetia
Additionally guyed tower
TOWERS IN WARFARE
* ^ Map, The Megalithic
* Fritz Leonhardt (1989), Towers : a historical survey, Butterworth Architecture, 343 pages.
Wikimedia Commons has media related to TOWERS .
* LCCN : sh85136296 * GND : 4203577-6 * BNF : cb11965217k (data) * NDL : 01058855