Hagia Sophia Grand Mosque - Ayasofya, Turkish - Islamic Architecture

Hagia Sophia is a great architectural beauty and an important monument both for Byzantine and for Ottoman Empires. Once a church, later a mosque, and now a museum at the Turkish Republic, Hagia Sophia has always been the precious of its time..
Hagia Sophia is one of the greatest surviving examples of Byzantine architecture.[6] Its interior is decorated with mosaics, marble pillars, and coverings of great artistic value. Justinian had overseen the completion of the greatest cathedral ever built up to that time, and it was to remain the largest cathedral for 1,000 years until the completion of the cathedral in Seville in Spain.[214]

The Hagia Sophia uses masonry construction. The structure has brick and mortar joints that are 1.5 times the width of the bricks. The mortar joints are composed of a combination of sand and minute ceramic pieces distributed evenly throughout the mortar joints. This combination of sand and potsherds was often used in Roman concrete, a predecessor to modern concrete. A considerable
The stone floor of Hagia Sophia dates from the 6th century.
The stone floor of Hagia Sophia dates from the 6th century. After the first collapse of the vault, the broken dome was left in situ on the original Justinianic floor and a new floor was laid above the rubble when the dome was rebuilt in 558.[221] From the installation of this second Justinianic floor, the floor became part of the liturgy, with significant locations and spaces demarcated in various ways using different-coloured stones and marbles.

The floor is predominantly made up of Proconnesian marble, quarried on Proconnesus (Marmara Island) in the Propontis (Sea of Marmara). This was the main white marble used in the monuments of Constantinople. Other parts of the floor, like the Thessalian verd antique "marble", were quarried in Thessaly in Roman Greece. The Thessalian verd antique bands across the nave floor were often likened to rivers.

The floor was praised by numerous authors and repeatedly compared to a sea.[124] The Justinianic poet Paul the Silentiary likened the ambo and the solea connecting it to the sanctuary with an island in a sea, with the sanctuary itself a harbour.[124] The 9th-century Narratio writes of it as "like the sea or the flowing waters of a river".[124] Michael the Deacon in the 12th century also described the floor as a sea in which the ambo and other liturgical furniture stood as islands.[124] During the 15th-century conquest of Constantinople, the Ottoman caliph Mehmed is said to have ascended to the dome and the galleries in order to admire the floor, which according to Tursun Beg resembled "a sea in a storm" or a "petrified sea".[124] Other Ottoman-era authors also praised the floor; Tâcîzâde Cafer Çelebi compared it to waves of marble.[124] The floor was hidden beneath a carpet on 22 July 2020.

The dome of Hagia Sophia has spurred particular interest for many art historians, architects, and engineers because of the innovative way the original architects envisioned it. The dome is carried on four spherical triangular pendentives, making the Hagia Sophia one of the first large-scale uses of this element. The pendentives are the corners of the square base of the dome, and they curve upwards into the dome to support it, thus restraining the lateral forces of the dome and allowing its weight to flow downwards The main dome of the Hagia Sophia was the largest pendentive dome in the world until the completion of St Peter's Basilica, and it has a much lower height than any other dome of such a large diameter.
Although this design stabilizes the dome and the surrounding walls and arches, the actual construction of the walls of Hagia Sophia weakened the overall structure. The bricklayers used more mortar than brick, which is more effective if the mortar was allowed to settle, as the building would have been more flexible; however, the builders did not allow the mortar to cure before they began the next layer. When the dome was erected, its weight caused the walls to lean outward because of the wet mortar underneath. When Isidore the Younger rebuilt the fallen cupola, he had first to build up the interior of the walls to make them vertical again. Additionally, the architect raised the height of the rebuilt dome by approximately 6 metres (20 ft) so that the lateral forces would not be as strong and its weight would be transmitted more effectively down into the walls. Moreover, he shaped the new cupola like a scalloped shell or the inside of an umbrella, with ribs that extend from the top down to the base. These ribs allow the weight of the dome to flow between the windows, down the pendentives, and ultimately to the foundation.[232]