Click images to enlarge.   Hagia Sophia | Dome Professor Robert Ousterhout Architectural Precedents Setting & Function Groundplan & Elevation Dome Structure & Structural Problems Innovative Trends Symbolic Resonance ------------------------ Back to Hagia Sophia Main Back to Briefing Main The central dome is the dominant theme of the building. Unlike earlier domed buildings which were circular in plan, such as the Pantheon in Rome, the dome of the Hagia Sophia rests above a rectilinear ground plan. This design requires an architectural element to accomplish the transition from square to circle. To solve this problem, pendentives, or spherical triangles, are used to bridge the space between the four supporting corner piers and the circular base of the dome. It is estimated that 105 tons of pressure per square meter are exerted on the major piers. Istanbul, Hagia Sophia, Interior view of the dome and the clerestory     To the east and west, the dome is flanked by half domes, and these are in turn braced by the conches of the exedrae. Istanbul, Hagia Sophia, Drawing Istanbul, Hagia Sophia, Drawing hagia sophia main briefing | image index | resources home page | site image index | site resources media center for art history, archaeology and historic preservation | columbia university