Historical Minarets in Bursa are Protected Against Earthquake

by Behlül Kula | Nov 25, 2021
Historical mosques are very important part of the architectural heritage in our country. Bursa, which was the first capital of the Ottoman Empire, has also many historical mosques. Considering the high seismicity level of our country, it is clear that a significant proportion of these structures are constantly facing earthquake hazards. Therefore, in this Project, the fragility curves of the historical minarets are obtained to estimate the damage risk under a possible earthquake. Moreover, applicable intervention methods respecting conservation principles are studied to improve the structural performance of the minarets.

Historical mosques are very important part of the architectural heritage in our country. Bursa, which was the first capital of the Ottoman Empire, has also many historical mosques. Considering the high seismicity level of our country, it is clear that a significant proportion of these structures are constantly facing earthquake hazards. Therefore, in this Project, the fragility curves of the historical minarets are obtained to estimate the damage risk under a possible earthquake. Moreover, applicable intervention methods respecting conservation principles are studied to improve the structural performance of the minarets.

You can find the detailed explanation about the project, coordinated by Prof. Dr. Alper İlki, below.

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Project Title: The analytical and experimental ıdentification of seismic performance and fragility curves of historical minarets of Bursa
Project Type: AFAD-UDAP
Project Coordinator: Prof. Dr. Alper İlki

Abstract: Historical mosques are very important part of the architectural heritage in our country. Bursa, which was the first capital of the Ottoman Empire, has also many historical mosques. Considering the high seismicity level of our country, it is clear that a significant proportion of these structures are constantly facing earthquake hazards. The earthquakes that occurred throughout the history have caused different levels of damage in almost all of these structures. The knowledge related to the repairing and reconstruction operations after the earthquakes can be followed in both the literature and the structures themselves. One of the distinctive structural parts of the mosques is minarets with their high symbolic values. The minarets are very slender compared to their mosques. Hence, the minarets are quite vulnerable to the earthquake effects and they are among the first damaged or destroyed structures during the major earthquakes. On the other hand, minarets are often ignored during the studies on the structural evaluation and improving structural performance of historical mosques.  The seismic safety of the historical minarets should be inspected based on the realistic approaches to maintain the safety of people during the daily use of the historical mosques and to guarantee their existence in the future. For this, the fragility curves of the historical minarets should be obtained to estimate the damage risk under a possible earthquake and to mitigate this risk. Moreover, the applicable intervention methods should be developed to improve the structural performance of the minarets. Therefore, in this project, performing an experimental and analytical study on the historical minarets in Bursa is planned. Although the minarets have similar forms, they displays considerable differences in terms of geometry, structural material and construction techniques. These differences have a decisive impact on the seismic behavior characteristics of the minarets as well the visual effects. Hence, the first step of the project is to conduct a comprehensive national-international literature survey related to the historic masonry minarets. The second one is to determine the typologies of the historical minarets in Bursa and to choose a typical example for each determined typology with an intention of conducting comprehensive studies on the selected examples of the minarets. The third one is to obtain the dynamic characteristics of the selected minarets with the ambient vibration tests. The fourth one is to perform shaking table tests on the minaret specimens. The fifth one is to perform modal analysis by forming structural models and to update the models by utilizing the ambient vibration tests. The sixth one is to produce the fragility curves of the selected minarets under the sufficient number of earthquake ground motions based on the results of the Incremental Dynamic Analysis. The seismic damage levels of the unexamined historical minarets in Bursa can be estimated using these fragility curves and these damages can be reduced by taking precautions if necessary. The seventh one is to propose applicable intervention methods for the investigated minarets with an intention of improving their seismic behaviors and to investigate the efficiencies of the methods by conducting structural analyses. The eighth one is to obtain the fragility curves of the minarets that intervention methods are applied and to determine the ratio of the decrement amount in seismic damage risk. The last one is to arrange a one daily workshop for discussing the obtained results. Briefly, the main aim of the project is to reduce damage risks of the historical minarets under possible future earthquakes. In order to realize this aim, the seismic performances of the minaret typologies are estimated, applicable intervention methods are proposed for improving their seismic behaviors and fragility curves of the inspected minarets are obtained.

İTÜ Faculty of Civil Engineering

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It can be accepted that the history of ITU Civil Engineering Faculty was commenced in 1727 by the establishment of Humbarahane during the era of Damat İbrahim Paşa. However, this attempt was to no avail due to the martyrization of the studwents of this school by the Janissaries.


In 1734, during the grand viziership of Topal Osman Paşa, classes related to Civil Engineering was being taught in Hendesehane, which was founded in Üsküdar. Similarly, this school was also closed after three years due to the opposition of the Janissaries. The reasons of the tragedy that occured in Battle of Chesma, 1770 were inadequacy of the ships and the ignorance of the Ottoman Navy.


Although the Atlantic Map (1513) and the Map of Europe and the Mediterranean Sea (1523) by Piri Reis were the leading pieces of the era, Ottoman viziers were so ignorant that they claimed it was impossible for the Russian Baltic Fleet to reach the Mediterranean Sea assuming that there were no sea connection. With the proposal from Gazi Hasan Paşa and Baron de Tott, Mühendishane-i Bahri-i Humayun was established during the time of Sultan Mustafa III, aiming to train naval construction engineers. Since Ottoman Empire did not have any engineering schools at the time, military engineering classes were taught by French engineers beginning from 1784. French lecturers had to return to their country in 1788 with the increasing suppression from Austria and Russia, which were unwilling for the development and thriving of Ottoman Empire. In 1759, during the Grand Viziership of Koca Ragıp Paşa, Humbarahane was reopened in Karaağaç, Haliç (Golden Horn) and continued to teach even though it was incompetent. In 1792, Lağımcı Ocağı and Humbaracı Ocağı (Guild of Sappers) were established.