From Past to Present: Investigating the Structural Performance of Hagia Sophia’s Dome

Abstract

Ageing heritage structures increasingly present safety hazards, especially in regions exposed to frequent seismic activity. Beyond their serviceability, these structures embody significant cultural, architectural, and engineering knowledge, making their preservation dependent on a clear understanding of their structural integrity. This thesis investigates the stability and seismic performance of the nearly 1,500-year-old masonry dome of the Hagia Sophia­­­—a brick and mortar structure that has endured multiple earthquakes in Istanbul, Turkey since its reconstruction in 537 AD. Despite this resilience, the dome exhibits cracking patterns that raise concern about its performance under future seismic events. Focusing specifically on the central dome, rather than the entire mosque, this project evaluates its behavior under both static and dynamic conditions. A graphic statics approach is applied to analyze the thrust distribution and assess geometric equilibrium. Additionally, a Level-Set Discrete Element Method (LS-DEM) model is developed to simulate the dome’s response to lateral loading, capturing sliding and rocking mechanisms that classical continuum methods can’t represent. Altogether, we gain deeper insight into the relationships between geometric stability and dynamic failure responses. The results contribute to a more complete understanding of hemispherical masonry domes, complementing existing finite element methods and experimental studies.