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Failure: Hagia Sophia Dome Failure
Location: Istanbul, Turkey
Year: 553, 557, 558, 869, 989, 1344
Type: Structural Failure

Hagia Sophia is a cathedral located Istanbul, Turkey (image 1) [a]. The original cathedral was finished in 360 A.D., but due to a future of riots, rebellions, and the fall of empires, the structure was rebuilt multiple times, each version more grand than the last. Due to this rich history, the cathedral has crowned the bodies of both the Christian and the Muslim world. It now stands as a museum under the Turkish Republic [b].

Hagia Sophia is world renown for the colossal dome that sits upon the cathedral (image 2,3). Also renown is the myriad of failures the dome experienced-“the dome of hagia Sophia partially collapsed in 553 and 557 and again in 989 and 1436 , always because of earthquakes” [c]. The first takes at the Hagia Sophia burned down due to fires started by riots; not until architect Isodorus of Miletus and mathematician Anthemius of Tralles were commissioned did the dome become a feature of the Hagia Sophia [d].

Knowing the materials they were using were weak in tension, the two architects initially planned to stabilize the dome by constructing butresses uniformly around its base. However, due to demands by the church that the cathedral below the dome must be in a cruciform shape with unequal arm lengths, such uniform stabilization was not possible [c].

The rigidity of domes caused a massive problem for this region-they are very susceptible to foundation problems, namely earthquakes [c].  “Two earthquakes (August 553 and December 557) caused cracks in the main dome and eastern half-dome” [d]. Not until year later in May of 558 did a third earthquake completely collapse the main dome of Hagia Sophia [d]. Following this disaster, the dome of Hagia Sophia was resurrected by Isodorus’ nephew, Isodorus the Younger. This construction, completed in 562, added 30 feet to dome’s height, resulting in its current height of 182 feet [d].

A fourth earthquake in 869 made one of two half domes surrounding the main dome collapse. A fifth earth quake in 989 severely damaged the dome of Hagia Sophia, necessitating new repairs undertaken by Armenian architect Trdat [d]. A sixth earthquake in 1344 caused new cracks in the dome, rendering previous attempts at buttressing the dome made in 1317 useless. Not until 1847-1849 was Hagia Sohpia stabilized by Swiss architects Gaspar and Guiseppe Fossati, who cinched the base of the dome with iron chains, solving the dome’s weakness in tension [c].

[c]-“How Structures Fail-Why Buildings Fall Down”. Matthys Levy and Mario Salvadori. W.W. Norton & Company: New York, 2002. Print.