Fortification
Fortifications are
military constructions and buildings designed for defense in
warfare. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs. The term is derived from the
Latin fortis and
facere .
Many military installations are known as forts, although they are not always fortified. Larger forts may class as fortresses, smaller ones formerly often bore the name of fortalices. The word fortification can also refer to the practice of improving an area's defense with defensive works.
Encyclopedia
Fortifications are
military constructions and buildings designed for defense in
warfare. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs. The term is derived from the
Latin fortis and
facere .
Many military installations are known as
forts, although they are not always fortified. Larger forts may class as
fortresses, smaller ones formerly often bore the name of
fortalices. The word
fortification can also refer to the practice of improving an area's defense with defensive works.
City walls are
fortifications but not necessarily called
fortresses.
The art of laying out a military camp or constructing a fortification traditionally classes as
castrametation, since the time of the
Roman legions. The
art/
science of laying
siege to a fortification and of destroying it has the popular name of
siegecraft and the formal name of poliorcetics. In some texts this latter term also applies to the art of building a fortification.
Fortification is usually divided into two branches, namely
permanent fortification and
field fortification. Permanent fortifications are erected at leisure, with all the resources that a state can supply of constructive and
mechanical skill, and are built of enduring materials. Field fortifications are extemporized by troops in the field, perhaps assisted by such local labor and tools as may be procurable and with materials that do not require much preparation, such as
earth, brushwood and light
timber. There is also an intermediate branch known as
semipermanent fortification. This is employed when in the course of a campaign it becomes desirable to protect some locality with the best imitation of permanent defences that can be made in a short time, ample resources and skilled civilian labor being available.
Medieval-style fortifications were largely made obsolete by the arrival of
cannons on the 14th century battlefield. Fortifications in the age of
blackpowder evolved into much lower structures with greater use of ditches and earth
ramparts that would absorb and disperse the energy of cannon fire. Walls exposed to direct cannon fire were very vulnerable, so were sunk into ditches fronted by earth slopes. This placed a heavy emphasis on the geometry of the fortification to allow defensive cannonry interlocking fields of fire to cover all approaches to the lower and thus more vulnerable walls. Fortifications also extended in depth, with protected batteries for defensive cannonry, to allow them to engage attacking cannon to keep them at a distance and prevent them bearing directly on the vulnerable walls. The result was
star shaped fortifications with tier upon tier of hornworks and
bastions, of which
Bourtange illustrated to the right is an excellent example. There are also extensive fortifications from this era in the
Nordic states and in Britain, the fortifications of
Berwick on Tweed being a fine example.
The arrival of explosive shells in the nineteenth century led to yet another stage in the evolution of fortification. Star forts of the cannon era did not fare well against the effects of high explosive and the intricate arrangements of bastions, flanking batteries and the carefully constructed lines of fire for the defending cannon could be rapidly disrupted by explosive shells. Worse, the large open ditches surrounding forts of this type were an integral part of the defensive scheme, as was the covered way at the edge of the counter scarp. The ditch was extremely vulnerable to bombardment with explosive shells.
In response, military engineers evolved the
polygonal style of fortification. The ditch became deep and vertically sided, cut directly into the native rock or soil, laid out as a series of straight lines creating the central fortified area that gives this style of fortification its name.
Wide enough to be an impassable barrier for attacking troops, but narrow enough to be a difficult target for enemy shellfire, the ditch was swept by fire from defensive blockhouses set in the ditch as well as firing positions cut into the outer face of the ditch itself.
The profile of the fort became very low indeed, surrounded outside the ditch by a gently sloping open area so as to eliminate possible cover for enemy forces, while the fort itself provided a minimal target for enemy fire. The entrypoint became a sunken gatehouse in the inner face of the ditch, reached by a curving ramp that gave access to the gate via a rolling bridge that could be withdrawn into the gatehouse.
Much of the fort moved underground, with deep passages to connect the blockhouses and firing points in the ditch to the fort proper, with magazines and machine rooms deep under the surface.
The guns however, were often mounted in open emplacements and protected only by a
parapet - both in order to keep a lower profile and also because experience with guns in closed
casemates had seen them put out of action by rubble as their own casemates were collapsed around them.
Steel-and-
concrete fortifications were common during the 19th and early 20th centuries, however the advances in modern warfare since
World War I have made large-scale fortifications obsolete in most situations. Only underground
bunkers are still able to provide some protection in modern wars. Many historical fortifications were demolished during the modern age, but a considerable number survive as popular tourist destinations and prominent local landmarks today.
See also
- List of fortifications
- List of forts
- Castra
Fort componentsTypes of fortsHistorical FortressesFortification and siege warfare ...
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