If the earth was a single state Istanbul would be its capital . -Napoleon Bonaparte
Index *Intro *History * Architecture Character *Structure *References
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A M A G N I F I C E N T A N CI E NT M E GA S T R U CT U R E
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Intro
Architectural type : Byzantine Location : Istanbul , North western Turkey ( Constantinople ) Designers : Isidore of Mieltus & Anthemius of Tralles Material : Ashlar , Brick Diementions : Length : 82 meter (269 ft)
Width : 73 meter (240 ft) Height : 55 meter (180 ft) History : Eastern Orthodox Cathedral (573 - 1204 A.D)
Cathdox Church Cathedral (1204 - 1261 A.D) Eastern Orthodox Cathedral (1261 - 1453 A.D) Imperial Mosque (1453 - 1931 A.D) Museum (1931 - present )
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History
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History Location : Hagia Sophia is located in Istanbul Turkey ( Constantinople )
Constantinople map
The mystical city Istanbul hosted many civilizations since centuries Which Byzantium and Ottoman Empires were both The most famous ones . Hagia Sophia Is one of the great Architectural building for both Byzantine Empire
And the Hagia Sophia means “Holy wisdom”
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Hagia Sophia Time Line Constantine's Church (360 A.D) : Known as The Great Church its the first Church built at the same location where was there A pagen temple , It was Constantius II who ordered to build The Church there about (360 A.D). This church was largely burned down in (404 AD)
Theodosius II's Church (405 A.D) : after the Constantine's (great church) was destroyed , Theodosius II ordered it to be repaired And he opened it again in (405 AD)
Theodosius II's Church
The church was completely destroyed during the Vandalism Of the Nika Revolt in (532 A.D)
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Hagia Sophia Time Line Justinian's Church ( Hagia Sophia ) (532 A.D) : after the Destruction of The second church, Justinian the Great ordered to rebuild What was damaged and destroyed but , the people were Against him because of the high taxes he has imposed In (532 A.D) the cathedral was constructed by 2 teams of 5000 Workers each lead by 50 masters. The work began on clearing The site after its destruction . He needed to keep the public from Rioting against him and restore faith in his reign. A major building project is a great way to occupy the idle hands He also wanted his new cathedral ready as quick as possible, He turned to two men skilled in science and mechanics To design the cathedral . Isidore of Miletus and Anthemius of Tralles
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Hagia Sophia Time Line Hagia Sophia Mosque : About a thousand years later in 1453 A.D , The Sultan of the Ottoman Empire, Mehmet II after they invasion Constantinople , He directly went to the ancient Byzantine cathedral of Hagia Sophia When he saw a man hacking the stones of the church and saying that this was a temple for infidels Lets destroy it . Mehmet II ordered the looting to be stopped and The church to be converted into a mosque.
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Hagia Sophia Time Line Hagia Sophia Museum : Nowdays the mosque has been converted into a museum.
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Architecture Character
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Architecture Character In the exteriors the grouping of the smaller domes round The larger central one was very effective, One of the most remarkable peculiarities of these churches Being that the tunnel vault retains it from externally, As in the case of a dome. In no style does the elevation So closely correspond with the section as in the Byzantine. An attempt was made to render the rough brick exteriors Of Roman times more pleasing, by the use of bands and Relieving arches of an ornamental character. A Byzantine building consists generally of a brick Carcase or shell, the Wall being sheeted with marble, And the vaults with mosaic, the marble columns and Cornices being added on the completion of this shell. The science of construction acquired by the Romans Cescended to the Byzantines. The construction Of the walls with a brick facing and concrete interior Is merely an extension of the Roman system. It was employed not only for walls, But also for vaults, bridges, and a aqueducts.
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Architecture Character The general form of the building being more or less decided; It was necessary to collect monolithic morale shafts, And it was necessary to have a certain knowledge where Such might be quarried or otherwise obtained, Before the foundations were prepared, for the columns Decided the height and points of support of the building. These columns once assured, the body of the structure Was proceeded with, as brickwork shell without further Dependence on the masons, who were only required To prepare the bases, capitals, and cornices, Everything else being completed as brick “Carcase”. The building was made of vast masses of thin bricks, The mortar composing half of the aggregate, When this had settled down and dried, the walls were sheeted With their marble covering, the vaults overlaid With mosaic and the pavement laid down. In this the carcase was completed at once, The bricklayers not having to wait for the masons, And further, by reserving the application of the marble Until the contracture was dry and solid. It was possible to bring together unyielding marble And brickwork with large mortar joints that must have Settle down very considerably. The dependence Of masonry unequally charged was a loading idea In Byzantine contraction.
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Architecture Character The quantity of mortar was So great that the brick at the times becomes secondary In height to the joints. Brick was the material preferred in The construction of churches; it lent itself best to all the Caprices of the architect. The interiors were always lined With marble and mosaics, or decorated with paintings. The form the bricks varied infinitely in Byzantine times, But the ordinary brick was like the Roman, An inch and half in thickness, and was always laid upon a bed Of mortar, at least half an inch in thickness. Moulds were used for the pieces forming cornices, And the shafts of columned when of this material were built Of circular bricks. Brick-making was the feature of The Byzantine period. The core of the wall was naturally Of concrete, as in the Roman period, but the manner In which the bricks of the casing were arranged contributed Greatly to the direction of the exterior of buildings. Byzantine architecture was developed by the use of brick In the frankest and fullest manner, especially in Domical vaulting. Byzantine art is the Greek spirit Working in Asiatic elements, for the dome on pendentives Was invented and perfected entirely in the east.
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Architecture Character Domed placed over square apartments which is called Pendentives, their based brought to a circle. Whereas in Roman architecture the dome mass as a rule Placed over a circular apartment. From the time when The architect permitted the forms of the vaults and Arches to appear in the exterior decoration of the facades, The regular entablatures of the Romans were abandoned And in the church of Santa Sophia we see fully developed Byzantine style. In the older building of Rome, The columns and entablatures could be and have been Removed without causing the ruin of the building. In Santa Sophia, the construction is reverted. It is columns and capitals being not merely ornamental, But really supporting the structure.
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Architecture Character In continuation of Greek principles the capitals even assume A novel form, appropriate to their new propose of receiving The springer of arches, the voussiors of which were always Square, and not set in receding planes as in so called Gothic architecture. The problem was to bring the arch And column to support the arch. This was done by shaping The block of marble which formed the capital so that a Simple transition from the square block to the circle of the Column was formed. There were 4 main types of capital Used by the Byzantines, and these are formed in Santa Sophia. The numerous round shafts of Santa Sophia Exhibit a remarkable and beautiful structural expenditure, By which the necking is entirely suppressed. And bronze annulets surround the shafts under the capital And above the base. This method prevents the shafts From sliding or splitting, and retains the lead beds from Being forced out by the weight, for large monolithic shafts, As they had to be set up contrary to the direction of the Quarry strata. In Byzantine, ornamental and structure Were intimately united.
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Architecture Character In the Byzantine period no church Was founded in which mosaic did not add it splendour To that of sculpture and perilous stones. In Byzantine buildings, then, the logical outcome Of Roman methods of construction is seen; Dome and vault are freed from the trabreated system, And advanced to the dignity of a style through the Acceptance of a novel principle and the discovery of an Architectural expression suited to it. The use of rough And small materials involved the constructive principle Of the arch, dome, and vault and these forms Were the elements of the new style.
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Architecture Character Hagia Sophia at Constantinople : The plan consists of a central space bounded by four massive Piers, 25 feet square , connected by semicircular arches , And supporting a dome ofc 107 feet in diameter , Ising above the pavement.
The base of this dome is pierced by 40 small windows , lighting the central area. Against the eastern and western Arches of the dome abut half-domes , thus a long oval Interior is formed. Within the depth of the south and North arches are galleries in 2 storeys , The upper being for women. In the spandrel walls , Which stand up on the front line of the gallery arcades , Are ranged tiers of narrow windows Giving additional light to the interior.
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Architecture Character In the exteriors the grouping of the smaller domes round The larger central one was very effective, One of the most remarkable peculiarities of these churches Being that the tunnel vault retains it from externally, As in the case of a dome. In no style does the elevation So closely correspond with the section as in the Byzantine. An attempt was made to render the rough brick exteriors Of Roman times more pleasing, by the use of bands and Relieving arches of an ornamental character. A Byzantine building consists generally of a brick Carcase or shell, the Wall being sheeted with marble, And the vaults with mosaic, the marble columns and Cornices being added on the completion of this shell. The science of construction acquired by the Romans Cescended to the Byzantines. The construction Of the walls with a brick facing and concrete interior Is merely an extension of the Roman system. It was employed not only for walls, But also for vaults, bridges, and a aqueducts.
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Architecture Character
The abutment of these side arches of the dome , Not having half-domes resting against them , Is taken by huge external buttresses. Out of these rectangular angles being filled it with domes . In front of the outer narthex is an entrance court surrounded By a colonnade. The great piers are constructed of squared Stones , the rest of the building is of brickwork. Internally the walls, piers , and floor are lined with coloured Marbles fixed to the walls by metal cramps , the vaults Are enriched with mosaics of the apostlesand angels on a Golden ground , and the columns are of the precious and Many- colored marbles , with bronze rings Connecting the shafts with capitals and bases.
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Architecture Character
Externally , the vaulting of the domes is visible , Being covered with lead 0.25 inch thick resting on wooden Battens placed immediately on the brick vaults. The minarets, shown in the illustrations , Have of course been added in Mohometan times. The mosaics are partially covered up and replaced By quotations from the Quran.
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Architecture Character
Hagia Sophia is the masterpiece of Byzantine architecture as The Parthenon is of Greek or the pantheon of Roman. Foundation stone laid by Justinian A.D. 532 , The central dome is 107 feet in diameter , And surrounded by 4 arches abutting on masses of Masonry 75 feet long and 25 feet wide. East and west Are semi-domes. Santa Sophia was used as a mosque and is covered with Saracenic decorations. The exterior is in Brick. And now used as a museum.
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Architecture Character
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Structure
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Structure Hagia Sophia has gigantic central space of 31m² marked out by four great peers. To span an area the size of Hagia Sophia's dome, the building material needed to be exceptionally light. The dome of Hagia Sophia is 56m high and over 31m across. It spans a nave 3 times wider than any gothic cathedral.
Nave
They had to think of a way to place the round dome onto the square base created by the piers. Plan of Hagia Sophia
Dome
Section of Hagia Sophia
The dome sits on top of 4 great arches in the center of the cathedral each 31m wide but the dome sits directly on the top most point of each arch. But without additional support, it would crack and collapse upon itself.
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Structure
Pendantives
A dome suspended over the square base to mark the nave. Means putting a circular structure on top of a square structure. And the architects solved this by using pendentives. This was the first time that pendentives such as those has been used to support a dome. The triangular pendentives were concave mincing the curve of the dome. They also counter acted the tendency of the dome into the piers that supported the arches channeling the weight down to the ground. They took a rectangular structure and put pendentives in it and change it into a circular structure and on top of the circular structure they built a cylinder and on top of the cylinder the put the dome. (how the first dome was built) The arches had to be massive which created problems. Because the arches generate significant horizontal thrust at the bottom. So the arch goes down and the bottom kick out. ( The cathedral was 140m long)
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They made an extension at either end and roofing it with a half dome, which gives support to the main arch.. They also added smaller semi dome, doubling the length of the nave without increasing the span of the supporting infrastructure.But they needed light material to build the dome, so they imported special lightweight bricks from Rhodes.
Structure The mortar between the bricks is thicker than the bricks and contains an amount of crushed bricks. It is made of the same material of the bricks resulting in a very strong bond between the bricks and the mortar. But still, the weight of the dome exerts a great load on the supporting piers pushing them out of alignment.
Stone
Mortar
On either sides of the nave, two access passages ran the entire length of the building, and directly above these were another two corridors lined by colonnades. The arches that form the corridor were built into the structural piers that hold up the dome. These arches were extended across the corridor to create four huge buttresses that channeled the thrust of the dome down to the ground absorbing the huge weight above them. Many of the features of the cathedral were made with stone which adds to the weight of the building resulting in more pressure on the over loaded structure.
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Structure The columns of the cathedral were made of marble, but they couldn’t afford to crave all of the columns from scratch, so they had to cut corners. At each end of the Hagia Sophia’s nave is a set of gigantic columns, some of them are at least 30 cm shorter than the others because they might have been reused.
The original plan has been to duplicate the width of the colonnade from the ground level in the gallery above. But that changed. When the building reached the upper level of the structure, the designers shortened the colonnade and altered the position of the upper pillars. (Maybe they couldn’t fine columns large enough for the upper level of the cathedral. Or the more reasonable explanation is that they wanted to finish it in a shorter amount of time.)
Original Plan
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Changes
Structure The weight of the arches started pushing the piers out of shape. The designed some of the piers to act like buttresses absorbing the weight of the dome and the arches supporting it. But as the weight of the great arches pressed upon them, the weak points began to shear. To solve that, they added reinforced arches within the existing buttress piers, they also have increased the height of the piers adding additional cross bracing and filling in the upper most arch to give it strength, but that wasn’t enough. We can see today how the weight of the dome tilted the columns outwards. The solution for that was a set of projections that can be seen outside of the cathedral, they work on deflecting the outward thrust of the piers down into the ground.
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Structure Due to the outward thrust of the walls, now meant the base on which the dome rests on is no longer square. Because of that, a perfect circle was impossible, so they had to build an elliptical dome with a shallow curve that could span the uneven dimensions, it sat on top of a cylinder which allowed light to go inside the dome, but it was unstable. It stood for 20 years until it was shaken by a massive earth quake that caused the dome to crack. A team of workers worked on repairing the damage. In 558 A.D, while the repairing was taking part, another earthquake caused the eastern part of the vault to fall down. The dome collapsed.
Later on, the dome was replace and they realized the core of the problem was the cylinder in which the dome was sitting. Getting rid of the cylinder would get rid of the weak link in the structure. So they remodeled the upper part in the north and the south arches altering the distance the dome needed to span. If the dome was made a perfect half sphere, the weight bearing down on the pendentives would no longer channel properly into the support, so they adjusted the radius of the dome to match the angle of the pendentives, which made it a more stable. (It took 4 years to repair the dome) They also built shock absorbers into the columns using Lead to base to colonnade base and also the capitals, which allows it to be flexible.
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Structure
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References *A history of architecture on the comparative way (P .192 - 203) (Banister F. Fletcher) *National geographic Megastructures Istanbul's Hagia Sophia (Video) *www.hagiasophia.com *Web sites for images
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