Jump to navigation Jump to search « Towers » redirects here. 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 turris Babel PDF-wires and are therefore, along with tall buildings, self-supporting structures.
Andreae substitue à la Tour de Babel des opinions les connaissances nées de l’étude et du travail, et cette très actuelle leçon porte encore ses fruits de nos jours. En quelques pages alertes , il renvoie le Rosicrucianisme à sa vérité : celle d’un orphelin prétentieux et vain qui entraîne les crédules dans les ténèbres de son ignorance.
Towers are specifically distinguished from « buildings » in that they are not built to be habitable but to serve other functions. 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. Towers have been used by mankind since prehistoric times. Some of the earliest towers were ziggurats, which existed in Sumerian architecture since the 4th millennium BC. Some of the earliest surviving examples are the broch structures in northern Scotland, which are conical towerhouses.
Other well known towers include the Leaning Tower of Pisa in Pisa, Italy built from 1173 until 1372 and the Two Towers in Bologna, Italy built from 1109 until 1119. 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. 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. In the United Kingdom, tall domestic buildings are referred to as tower blocks. 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. 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.