Figure 3. Arch forms.

ROOF

A roof is covering of the top of a building, serving to protect against rain, snow, sunlight, wind, and extremes of temperature. Roofs have been constructed in a wide variety of forms – flat, pitched, vaulted, domed, or in combinations – as dictated by technical, economic, or aesthetic considerations.

The earliest roofs constructed by man were probably thatched roofs that were made of straw, leaves, branches, or reeds; they were usually set at a slope, or pitch, so that rainfall could drain off them. Conical thatched roofs are a good example of this type and are still widely used in the rural areas of Africa and elsewhere. Thicker branches and timbers eventually came to be used to span a roof, with clay or some other substance pressed into the interstices between them. Gabled and flat roofs were possible with these materials. With the invention of brick and cut stone for building, the basic roof forms of the dome and vault appeared.

Two main types of roofs are flat roofs and sloping ones. The flat roof has historically been widely used where the climate is arid and the drainage of water off the roof is thus of secondary importance. Flat roofs came into widespread use in Europe and America in the19th century, when new waterproof roofing materials and the use of structural steel and concrete made them more practical. Flat roofs soon became the most commonly used type to cover warehouses, office buildings, and other commercial buildings, as well as for many residential structures.

Sloping roofs come in many different varieties. The simplest is the lean-to, or shed, which has only one slope. A roof with two slopes that form an “A” or triangle is called a gable, or pitched, roof. This type of roof was used as early as the temples of ancient Greece and has been a staple of domestic architecture in northern Europe and America for many centuries. It is still a very common form of roof. A hip, or hipped, roof is a gable roof that has sloped instead of vertical ends. It was commonly used in Italy and elsewhere in southern Europe and is now a very common form in American houses. Gable and hip roofs can also be used for homes with more complicated layouts. The gambrel roof is a type of gable roof with two slopes on each side, the upper being less steep than the lower. The mansard roof is a hipped gambrel roof, thus having two slopes on every side. It was widely used in Renaissance and Baroque French architecture. Both of the aforementioned roof types can provide extra attic space or other room without building an entire additional floor.

The vault is a parallel series of arches used to form a roof, the most common form being a cylindrical or barrel vault. Vaults came into their greatest prominence in Gothic architecture. The dome is a hemispherical structure that can serve as a roof. Vaults and domes do not require a supporting framework directly below the vaulting because they are based on the principle of the arch, but flat and gable roofs frequently require internal supports such as trusses or other bracing. A truss is a structural member that is composed of a series of triangles lying in a single plane. Thin-shell roofs using concrete reinforced with steel rods can produce domes and barrel vaults that are only three inches thick yet span immense spaces, providing unobstructed interior views for stadiums and amphitheatres. In cantilevered roofs, a roof made of thin precast concrete is suspended from steel cables that are mounted on vertical towers or pylons of some sort.

The external covering of a roof must prevent rainfall or other precipitation from penetrating a building. There are two main groups of roof coverings. One group consists of a waterproof membrane or film that is applied as a liquid and that repels water by its utter impermeability after it has dried; the tar that is used to coat roofing felt is the prime example of this type. The other group consists of pieces of a waterproof material that are arranged in such a way as to prevent the direct passage of water through the joints between those pieces. This group includes shingles made of various materials, tiles made of baked clay or slate, and corrugated sheets of steel, aluminum, lead, copper, or zinc. Flatroofs are normally covered with roofing felt and tar, while sloped roofs are generally covered with shingles or sheet metal.

Word list:

roof (n) – дах

covering (n) – покриття

flat roof – плоский дах

pitched roof – похилий, схилий дах

vaulted roof – склепінчастий дах

domed roof – купольний дах

thatch (v) – покрити соломою

straw (n) – солома

reed (n) – очерет

pitch (n) –нахил

drain off (v) – скотитися

conical (adj) – конусний

interstice (n) – щіль, проміжок

gabled roof – гострокутний дах

cut stone – тесаний камінь

warehouse (n) – склад

lean-to (n) – однопохилий дах

shed (n) – навіс

gable roof – двопохилий дах

hip/ hipped roof – чотирипохилий дах, вальмовий дах

tar (n) – смола, гудрон

layout (n) – планування

gambrel roof – вальмовий дах з пониженими вальмами

mansard roof – мансардний дах

aforementioned (adj) – вищесказаний

attic (n) – аттик, фронтон

barrel vault – циліндричне склепіння

hemispherical (adj) – напівсферичний

truss (n) – ферма

bracing (n) – кріплення

thin-shell roof – тонкостінне покриття

cantilevered roof – консольний дах

precast concrete – збірний залізобетонний елемент

pylon (n) – пілон, опора

precipitation (n) – опади

shingle (n) – покрівельна дранка

tile (n) – черепиця

baked clay – обпалена глина

slate (n) – шифер

corrugated (adj) – рифлений, гофрований

roofing felt – толь, рубероїд

sheet metal – листовий метал

Answer the questions.

1. What is a roof?

2. What forms of roof do you know?

3. What do the forms of roofs depend on?

4. What do you know about the earliest roofs?

5. What are the main two types of roofs?

6. What can you tell about flat roofs?

7. What varieties of sloping roofs do you know?

8. Do vaults and domes require a supporting framework? Why?

9. What must the external covering of a roof prevent?

10. What two main groups of roof coverings are there?

11. What are flat roofs normally covered with?

12. What are sloped roofs are generally covered with?

Exercise 36. Translate into English.

1. Призначення даху – захист від дощу, снігу, вітру та сонячного проміння.

2. Форма даху залежить від технічних, економічних та естетичних завдань.

3. Солом’яні дахи – це найперші форми покриттів.

4. У нашому місті багато споруд з плоскими дахами.

5. Споруда, що зараз будується, матиме двопохилий дах.

6. Мансардний дах – це чотирипохилий дах з двома нахилами з кожного боку.

7. Склепіння – це серія паралельних арок, які формують дах. Вони бувають циліндричної форми.

8. Оскільки зовнішнє покриття даху захищає від опадів, воно повинно бути виготовлене з водонепроникного матеріалу.

9.Плоскі дахи зазвичай покривають толем та смолою, а похилі дахи– покрівельною дранкою або листовим металом.

ARCH

In architecture and civil engineering, an arch is a curved member that is used to span an opening and to support loads from above.

Figure 2. Parts of a circular arch  

Arch construction depends essentially on the wedge. If a series of wedge-shaped blocks (in which the upper edge is wider than the lower edge) are set flank to flank the result is an arch. These blocks are called voussoirs. Each voussoir must be precisely cut so that it presses firmly against the surface of neighbouring blocks and conducts loads uniformly. The central voussoir is called the keystone. The point from which the arch rises from its vertical supports is known as the spring, or springing line. During construction of an arch, the voussoirs require support from below until the keystone has been set in place; this support usually takes the form of temporary wooden centering. The curve in an arch may be semicircular, segmental (consisting of less than one-half of a circle), or pointed; non-circular curves can also be used successfully.

In masonry construction, arches have several great advantages over horizontal beams, or lintels. They can span much wider openings because they can be made from small, easily carried blocks of brick or stone, as opposed to a massive, monolithic stone lintel. An arch can also carry a much greater load than a horizontal beam can support.

Arches were known in ancient Egypt and Greece but were considered unsuitable for monumental architecture and seldom used. The Romans used the semicircular arch in bridges, aqueducts, and large-scale architecture. In most cases they did not use mortar, relying simply on the precision of their stone dressing. The Arabs popularized the pointed arch. Medieval Europe made great use of the pointed arch, which constituted a basic element in Gothic architecture. In the late Middle Ages the segmental arch was introduced. This form and the elliptical arch had great value in bridge engineering because they permitted mutual support by a row of arches, carrying the lateral thrust to the abutments at either end of a bridge. Modern arches of steel, concrete, or laminated wood are highly rigid and lightweight, so that the horizontal thrust against the supports is small; this thrust can be further reduced by stretching a tie between the ends of the arch.

Catenary or Parabolic arch	Elliptical arch	Equilateral pointed arch	Horseshoe arch
Inflexed arch	Ogee arch	Lancet arch	Reverse ogee arch
Round or Semi-circular arch	Segmental arch	Three-foiled cusped arch	Shouldered flat arch
Three-centered arch	Tudor arch	Rampant round arch	Triangular arch

Figure 3. Arch forms.

Word list:

arch (n) - арка

curved member – зігнутий елемент

span (v) – перекрити

wedge-shaped (adj) – клиновидний

voussoir (n) – клинчаста цегла

keystone (n) – замковий камінь

spring/ springing line – лінія п’ят арки

centering (n) – кружало арки

pointed (adj) – шпилястий

arc (n) – дуга

lintel (n) – перемичка

buttress (v) – підсилити

stone dressing – обробка каменю

lateral thrust – бічний тиск

laminated wood – пластинчаста деревина

parabolic arch – параболічна арка

catenary arch – ланцюгове аркове склепіння

equilateral pointed arch – рівностороння шпиляста арка

horseshoe arch – підковоподібна арка

inflexed arch – зігнута всередину арка

ogee arch – килеподібна арка

lancet arch – ланцетоподібна арка

round or semicircular arch – кругла чи напівкругла арка

segmental arch – сегментна акра

three-foiled cusped arch – трьохпелюсткова загострена арка

shouldered flat arch – плоска арка з заплічником

three-centered arch – трьохцентрова арка

elliptical arch – еліптична арка

Tudor arch – арка Тюдора

rampant round arch – повзуча кругла арка

triangular arch – трикутна арка

Дата добавления: 2015-10-26