From the history of Dome construction

The dome is regarded as the three- dimensional counterpart of the arch. In its true circular form, a vertical arch is rotated around a vertical axis and sweeps out, at every level, a continuous circular horizontal ring.

The simple dome, set on the ground, was the first manmade spatial enclosure.

The dome, constructed with horizontally bedded rings and sharply pointed profile, had already achieved monumental proportions by about the 14^th century BC in the great tombs at My cento. The full development of the freestanding dome owed much to Roman concrete.

The later Western development was initiated by an achievement that, in the circumstances, of the time, probably exceeded that of Hadrian's architect of the Pantheon dome. This was Brunelleschis construction of the dome of Florence Cathedral in the 15^th century. The main difficulty in that construction was the octagonal plan form which Brunelleschi was constrained to follow throughout the height of the dome itself. His idea was to construct it as if it were a circular Dome of the same internal diameter as the diagonals of the octagon - a diameter that slightly exceeded that of the Pantheon dome.

The center of the millennium celebrations is the Millennium dome in Greenwich, Britain, since the Greenwich meridian finds its origin there.

The architect of this largest assembly building in the world is Richard Rogers.

The Dome provides an enclosure for the exhibition. The concept of its roof is very simple-tensioned steel cables are arranged radially on the surface of the dome and held in space by hangar and tie down cables. The surface is defined as a spherical cap. Between the cables, tensioned coated fabric is used as cladding. Both the tensioned cables and cladding carry the loads by deflection accompanied by increase in tension.

The forces in the cables, 40 tonnes in each radial line have to be resisted at the centre where they come together and at the boundary where they are anchored. In the centre of the roof there is a 30 m diameter tension ring consisting of 12-48 mm diameter cables which carry a total of 700 tonnes.

At the edge the forces are resisted by vertical ground anchors going 12m down into the gravel layers and horizontally by a concrete ring beam 1000m in circumference, which carries the loads in compression.

VII. Complete the following sentences

1. The dome is regarded as the three - dimensional counterpart of__

a) The stanchone b) the roof c) the arch

2. The first primitive dome form, set on the ground, was a manmade spatial __

a) house b) tomb c) enclosure

3. The dome of__is the first renaissance double dome

a) Santa Croce b) Siena Cathedral c) Florence Cathedral

4. The Millennium Dome provides an enclosure for __

a) storage b) exhibition c) stadium

5. The Millennium Dome is the largest assembly building in__

a) Britain b) Europe c) In the world

6. The tensioned cables and cladding carry the loads by deflection accompanied by increase in__

a) compression b) tension c) thickness

Date: 2015-12-11; view: 1279