Вариант 3

ARCHES

Throughout most of architectural history, the arch has been the chief means of overcoming the spanning limitations of single blocks of stone or lengths of timber.

There were three types of arches in ancient architecture. One, which survives today in Mycenean cyclopean construction, consisted of only three rough blocks of stone, the central one somewhat larger than the gap between the other two and wedged between them. A second, of which monumental examples survive in Egypt from the 3^rd millennium BC, consisted of only two long blocks inclined toward one another as an inverted V-shape. This form was probably constructed even earlier in timber. The third, of which surviving examples are very widespread, was what is commonly known as the false or corbeled arch.

None of these early forms was very efficient. Spans rarely exceeded 6 ft 6 in. (2 m). The spanning of substantially wider gaps called for true arches constructed on centering from large number of bricks or stone voussoirs Small true brick arches appeared first in Mesopotamia and Egypt.

From the first century AD the Romans began to use concrete in place of cut stone for all the longer spans.

Liter brick and stone arches departed from Roman precedents mainly; in adoption of other profiles. Of these, the most important were the pointed profiles of most Islamic and of Gothic arches. The Islamic form appeared first and was preceded by a Sassanian form of roughly parabolic profile

The chief merit of the pointed profile was probably the ease with which it could be used in ribbed vaults of any plan shape and, without aesthetic inconsistency, throughout structures that vaulted in this way.

Early cast-iron arches of the late 18^lh and early 19^th centuries all closely resembled braced timber arches. Later steel and reinforced-concrete arch­es have usually been given the necessary stiffness simply by the adoption of an I-shaped, boxlike, or tubular cross section.

AFTER - TEXT EXERCISES

1. Give the Russian equivalents.

• the chief means of overcoming the spanning limitations of single blocks of stone

• the 3^rd millennium BC

• two long blocks inclined toward one another

• the false or corbelled arch

• stone voussoirs

• the necessary stiffness

• tubular cross section

2. Divide the verbs into two groups: regular or irregular. Give three forms of the verb.

Example: to consist-consisted-consisted

to know-knew-known

to begin, to be, to build, to resemble, to survive, to depart, to use, to construct, to give.

3. Translate into English.

1. Арка - криволинейное перекрытие проёмов в стене ( окон, ворот, дверей ) или пролетов между опорами. 2. Клинчатая арка выкладывается из камней клинчатой формы или из прямоугольных камней с клинообразными швами. 3. Ложная арка выполняется путём горизонтального напуска камней, не дает бокового распора. 4. Стрельчатая арка состоит из двух пересекающихся под углом дуг.