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hibis   Curiosity.
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this page,  architecture -  techniques and materials, master pieces of work
French

There does not remain lots of oldest cities and dwellings but most often only their monuments, patiently rectified and restored, which - if stone were used - testify about them.

Dwellings were built with materials much less resistant (wood, plants, raw bricks). One observes sometimes sketches on the ground and some clue (fire place, backyard, storage..). Troy (Turkey) is hidden under 6 or 7 layers of cities built during centuries, and the huts of Gallic are only reconstituted. Egyptian villages let only imagine what they could be, although in this country, dry sand authorised a very exceptional conservation.

It should be said that all it is wooden made has generally disappeared, well before fabrics and leather.

Finally, earthquakes destroyed a lot too, as for the greek monuments, the French forth crusade.

Characteristics of these monuments, palate or temples, often astonish. Here are two examples, particularly surprising. Twisted, the Parthenon on the Acropolis ? (Athens, Greece).

Its large sides are not rectilinear but slightly curved of a tenth centimetres; in the same way, its columns are slightly tilted towards the interior. Such elegance is finally due to a daring prospect.

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The theatre of Epidaure, Greece, Peloponese.

Have you ever listened to the noise of a match which one rubs ? then that of the breath, much more subtle, which precedes the flame ?

 Well, placed at the highest steps of this huge theatre, you will hear it, far away from the centre, like we heard it ourselves.hibicustour

Raw brick.

In poor and dry countries, as Egypt, Mexico, Sahel Africa... one can see villages of indefinable colour, rather greyish. Their houses are not always built in breeze blocks, but often out of raw brick, i.e. with kneaded and moulded ground bricks, dried in open air. Poor material thinks we; it is only partly true, because they offer a higher comfort by their quality of insulation, much better than that of cooked bricks. A decade ago, an architect had planned to build thus hotels and another buildings with several floors. I retrieve him at the Paris 2004 exhibition. Buildings exist, said he to me, even in Paris, of ground strongly pressed named "pisé", very hard. He propose now modern furniture (seat..), panneling...; contact to : mehdi@mehdidellagi.com

Cooked Brick. The cooked brick, still very much used nowadays, had its hours of glory at ancient times, not only for the construction of the architectural structure, but also for the completion, the fontages and mural decoration. Many houses and buildongs we can call recent, shows brick decorations (varous colors, twists, checkerworks..), remain everywhere.Thus under old Arab civilizations, the places of worship were built with cooked bricks, who ensured also external decoration. Until the 12 d, 13 d century, roughly speaking. When the fashion had been fading, or the technique progressing, platings were used for the large mosques, in Ispahan (Iran), in Baghdad (Iraq), Cairo Egypt), or for the Taj Mahal mausoleum (India), whose carcass work  were always realized with bricks. A large mosque in Ispahan would have required 18 million bricks and 475 thousand enamelled squares..

Granite or limestone ?

Egyptians thought that the granite was most resistant : yes, but for both wear and compression, not for the inflection. Lintels broke and the ceiling of the room of the tomb of Cheops is cracked, although supporting only little weight. They then returned to limestone for the framings, much more resistant
 

The Roman concrete

The Pantheon (Rome, year 124 after J.C) is covered by a gigantic cupola (more significant than that of Saint-Pierre): this cupola, partitioned inside of small boxes, is built out of cast concrete (moulded into a system of very elaborate formwork).

The walls, thick and ventilated by two circular corridors consist of two rows of bricks inside whose concrete is run. The Roman concrete consists of hardcores of stone or brick and puzzolane (volcanic ground, well-known by gardeners).

The Roman arch is inspired by both the Greek and the étrusque technique. But the Romans add the invention of the concrete to it. The arches and vaults are reduced and connections simplified. The Roman arch will be replaced by the Gothic arch, ( We think appeared first in France,  then in England, Germany etc).

The discovery of this concrete allowed to build much more quickly and with a certain lightness. The "Pont du Gard" (bridge of Gard), nearby Nimes, was built with this technique (extrernal stones, insidefilled in with concrete). This invention has however wanished, falling off mememories. Then,  ceilings of our cathedrals re-use the heavy stone !


New techniques were developed to make the concrete much more resistant; among those, vibrating brings a better cohesion and densifie it. Metal stems put into concrete reinforces it at inflection and makes it definitely less breakable. Lastly, this reinforced concrete can itself be built-in under a very strong traction, applied on the iron stems (ex : pylons), which is slackened when the concrete is dried and hard enough, thus forcing it under compression (it is called concrete prestressed).

Modern construction uses also the welded metal beams; beams and current concrete are at the base of the towers which enter each other into competition in the whole world for their height. Glass and light partitions supplement the external and interior preparing.

The walls thus do not support any more the floors and are not any more "bearing" like were those of the first pyramidal buildings of New York, crushed by the almostweight of blind walls at the bottom.

Enormous structures of steel and concrete, acting as quality of columns or beams, often hollow to receive the technical installations, now support concrete plates on which are literally hung the frontages (glass and panels).

Besides these insane rises of towers, these techniques also allow an "horizontal" work to cover great surfaces as the Exhibition site of La Defense (Paris), or the last hall of Roissy airport.

Although multi-layer wood entered in competition, stuck and bolted, like more recently the fabric. The elegance and the lightness of the fabric has been rediscovered by architects who cover now small passages or immense surfaces with fabrics strongly tended by a grid of cables sustained by pylons. and beams
It's crazy ! A new technology, inspired by inflatable structures, has created the inflatable beam . It is a steel cable twisted helically around an inflatable plastic cylinder, which ensures the rigidity of the steel spiral, replacing the intermediate beam system intertwined that would normally be required. This system, low gas loss, can imagine the forms at will.

Bamboo. The bamboo can grow more than one meter per day. With the time, it is getting laden out with silica and becomes hard enough to acquire both a higher flexibility  and resistance than steel. It even uses blades. Edison made its first electric lamp with it (silica and carbon).  In China, one always assembles buildings and skyscraper with scaffolding of tied bamboos. Up to 421 meters for Jin May Tower ! I saw thus erect a building in Hong Kong, without stopping the  circulation on the pavement ! the structure was lighter than this one, which must fit to other safety requirements. One now mingles steel with it to facilitate the assembly because the technique requires an unquestionable expertise. The bamboo is bound and not nailed because it split easily itself. In Laos, a house assembled in three months by three men lasts a half century !


Gothic cathedral and its "intersecting ribs", a particularly complex work due to the connections of curved surfaces.

The stone roofs involve a serious technical problem, of course because of the weight, but especially by the external push which is exerted on the walls :
To resist, the Roman buildings have large thick walls, small and rare openings and reinforcements by low walls forming of the edges. The Gothic art, from the 11 th century, which lets enter the light by the many and broad openings, calls especially upon the complex jambs and other arches (propping up); they are in great number, but cut out and carved, they belong to the decorations.

To prevent its walls from being quartered, Notre Dame de Paris offers superb ones to us and it is not decoration.

With a stone roof in vault, without no cross beam being pressed on the walls, the weight of the roof pushes pushes the walls towards outside.


The blue mosque, Istanbul.

The Mosques are surrounded by smaller spaces and low, also covered of cupolas, or half-cupolas, which "shoulder" the walls of the central room. Ste Sophie concerns the same principle and one can say that propping up them of our cathedrals are placed here inside to increase useful space (personal interpretation)


Double octogonal cupola for the cathedral of Florence.
Completed in 1436, the cupola failed to never be built so its dimensions were exceptional (the tower made nearly 50 meters in diameter and height.)

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Architect Brunelleschi designed a double brick cupola.
these two cupolas of brick are liked together with beams and small walls. the inside diameter of the first coupola is 45 m and its thickness is 0,70 m. Between them, corridors and staircases to go at the top. The thickness of the external coupola is 2,25 m. Total thickness : 10 m;  weight: 25.000 tons for the whole !  (Television FR3 )

 

The unit is aerated : on the right, in white, one see an opening practised through he 2,25 m thickness; also lighting.

One circulates between the two cupolas whose slopes are obvious here, compared to the vertical passage (opposite, in black). Room remaining: 10m - (0,70+2,25) = 62, 25 cm.

 
Beams and low walls ensure the rigidity of the two cupolas. One sees one of the cross beams of chestnut which binds the cupolas walls.

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