Structural Evaluation of an Ancient Egyptian Obelisk in Istanbul

Abstract

The "Obelisk of Theodosius" is one of the most important monuments located in the former Hippodrome in Istanbul, Turkey. The Obelisk with its sculpted base is 24.77 meters in height today, but historical recordings indicate that it was evidently higher originally. Additionally, the recordings show that some of the parts were left behind in Egypt due to transportation. The Obelisk has been exposed to many natural devastating events, particularly strong earthquakes. The monument is in a seismically very active region, Istanbul, located near one of the most devastating active faults of Turkey, the North Anatolian Fault. For the preservation of this obelisk, it is important to evaluate its seismic performance. For this purpose, in this study, the structural dynamic characteristics and the response of the obelisk were investigated. To achieve this aim, a numerical model was created using a finite element approach. In addition to this, real ground motion data were analyzed in this study. The most important finding of the study is that although the obelisk had experienced devastating earthquakes for a long time, revealed deformation is not noticeable. Its strength against earthquakes is most likely related to its constructed materials.

A numerical study on seismic risk assessment of historic masonry towers: a case study in İstanbul

“…Istanbul is reportedly under threat from an earthquake with a magnitude of Mw 7.0 [15]. Four earthquakes with magnitude of 9 or higher occurred in Istanbul and its surroundings between the 16th and 20th centuries, according to the Historical Earthquake Catalogue for Turkey [5]. Investigating the seismic behaviour of the historical Nusretiye (Tophane) Clock Tower is intriguing given that Istanbul is preparing for a significant earthquake with a moment magnitude of greater than 7.0.…”

“…In this study, Nusretiye Clock Tower's seismic performance was assessed utilizing a discrete element method (DEM). With this approach, the seismic response of masonry buildings is captured using precise mechanical and geometrical features [2][3][4][5][6][7].…”

Analysis of seismic parameters for the earthquake vulnerability assessment of Nusretiye (Tophane) Clock Tower

“…According to these maps, the selected region is considered to show a seismic gap for an earthquake potential 4.5 of M up to 7.4. In addition to these earthquakes, Turkey and Environment Historical Earthquake Catalogue between the 16th and 20th centuries indicated four earthquakes with 9 or higher intensity occurred in Istanbul and its surroundings (Polat and Saygılı 2020). Since the İstanbul faces a significant earthquake with a moment magnitude above 7.0, it is worthwhile to understand the seismic behaviour of historical Nusretiye (Tophane) Clock Tower.…”