Author(s): CakmakAS, DavidsonR, MullenCL, ErdikM
Recent results of field measurements and finite element studies of the Hagia Sophia, a 6th century masonry edifice, in Istanbul, Turkey, provide insight to the structure's response to dynamic loads. The church contains four great brick arches springing from stone piers that offer primary support for a 31-meter diameter central dome and two semidomes. Eigenvalue analyses using finite element models of the primary dome support structure provide estimates of mode shapes and frequencies for the structure. The material properties for the model are calibrated to match ambient vibration measurements. Motions induced by a recent 4.8 magnitude earthquake are discussed. Frequency and time domain analyses are used to identify mode shapes and frequencies. Analysis of distinct subintervals of the recorded motion, demonstrates a subtle variation of the frequency with increasing intensity. Animation of measured responses relate the mode shapes and frequencies of the eigenvalue model to the actual response of the structure.