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Рис. 177
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Parapet И
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A parapet is a barrier which is an extension of the wall at the edge of a roof, terrace, balcony, or other structure. Where extending above a roof, it may simply be the portion ofиan exterior wall that continues above the line of the roof surface, or may be a continuation of a vertical feature beneath the roof such as a fire wall or party wall. Parapets were originally used to defend buildings from military attack,Сbut today they are primarily used as guard rails and to prevent the spread of fires (рис. 178–181).

Рис. 178

Рис. 179

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Рис. 180			Д		Рис. 181
The word comes ultimately from the Italian parapetto (parare = to
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cover/defend and petto = breast). The German Иterm Brustwehr has the same
significance.	б
Parapets may be plain, embattled, perforated or panelled, which are not
mutually exclusive terms.
и
Plain parapets are upward extensions of the wall, sometimes with a
coping at the top and corbel below.
Embattled parapets may be panelled,				but are pierced, if not purely as

stylistic device, forСthe discharge of defensive projectiles.

Perforated parapets are pierced in various designs such as circles, trefoils, or quatrefoils.

Panelled parapets are ornamented by a series of panels, either oblong or square, and more or less enriched, but not perforated. These are common in the Decorated and Perpendicular periods.

Parapets surrounding roofs are common in London. This dates from the Building Act of 1707 which banned projecting wooden eaves in the cities of Westminster and London as a fire risk. Instead an 18-inch brick parapet was required, with the roof set behind. This was continued in many Georgian houses, as it gave the appearance of a flat roof which accorded with the desire for classical proportions.

Many firewalls are required to have a parapet, a portion of the wall extending above the roof. The parapet is required to be as fire resistant as the lower wall, and extend a distance prescribed by building code.

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Parapets on bridges and other highway structures (such as retaining walls) prevent users from falling off where there is a drop. They may also be meant to restrict views, to prevent rubbish passing below, and to act as noise barriers.

Bridge parapets may be made from any material, but structural steel, aluminium, timber and reinforced concrete are common. They may be of solid or framed construction.

In European standards, parapets are defined as a sub-category of "vehicle restraint systems" or "pedestrian restraint systems".

Portico

A portico (from Italian) is a porch leading to the entrance of a building, or extended as a colonnade, with a roof structure over a walkway, supported by columns or enclosed by walls. This idea was widelyИused in Ancient Greece and has influenced many cultures, including most Western cultures.

States Capitol, the portico adorning the Pantheon in Rome and the portico of University College London.

Some noteworthy examples of porticosДare the East Portico of the United

Bologna, Italy, is famous forАits porticos. In total, there are over 45 km (28 mi) of arcades, some 38 in the city center. The longest portico in the world, about 3.5 km (2 mi), extendsбfrom the edge of the city to Sanctuary of the Madonna di San Luca. In Turin, Italy, porticos stretch for 18 km (11 mi).

Palladio was a pioneerиof using temple-fronts for secular buildings. In the UK, the temple-front applied to The Vyne, Hampshire was the first portico applied to an EnglishСcountry house (рис. 182, 183).

Рис. 182

Рис. 183

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Spire

A spire is a tapering conical or pyramidal structure on the top of a building, particularly a church tower. Etymologically, the word is derived from the Old English word spir, meaning a sprout, shoot, or stalk of grass.

Currently, the largest spire to be part of the architecture of another building is the spire mounted on the recently completed Q1 residential tower on the Gold Coast in Australia (рис. 184–188).

					И
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Рис. 184	и				Рис. 185
С

Рис. 186

Рис. 187

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on circular towers and turrets, usually of small diameter.И

Рис. 188

cathedrals, generally with towers that are Дsquare in plan. While masonry spires on a tower of small plan may be pyramidal, spires on towers of large plan are

Traditional types of spires. Conical stone spires: These are usually found

generally octagonal. The spire is supportedАon stone squinches which span the corners of the tower, making an octagonal plan. The spire of Salisbury

Masonry spires: These are found on medieval and revival churches and

Cathedral is of this type and isбthe tallest masonry spire in the world, remaining substantially intact since the 13th century. Other spires of this sort include the

south spire of ChartresСиCathedral, and the spires of Norwich Cathedral, Chichester Cathedral and Oxford Cathedral.

Openwork spires: These spires are constructed of a network of stone tracery, which, being considerably lighter than a masonry spire, can be built to greater heights. Many famous tall spires are of this type, including the spires of Strasbourg Cathedral, Ulm Minster, Vienna Cathedral, Prague Cathedral, Burgos Cathedral and the twin spires of Cologne Cathedral.

Complex spires: These are stone spires that combine both masonry and openwork elements. Some such spires were constructed in the Gothic style, such as the north spire of Chartres Cathedral. They became increasingly common in Baroque architecture, and are a feature of Christopher Wren's churches.

Clad spires: These are constructed with a wooden frame, often standing on a tower of brick or stone construction, but also occurring on wooden towers

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