Almost all historical minarets in Turkey were constructed using cut stone, masonry blocks or combination of these two materials. The structural and geometrical properties of each masonry minaret, or slender tower structure, depend on many factors including the structural knowledge and applications at the time of construction, experience of the architect or engineer, seismicity of the region, and availability of construction materials in that area. Recent earthquakes in Turkey have shown that most masonry minarets in high seismic regions are vulnerable to structural damage and collapse. In this study, in order to investigate the dynamic behavior of historical unreinforced masonry minarets, three representative minarets with 20, 25, and 30 m height were modeled and analyzed using two ground motions recorded during the 1999 Kocaeli and Duzce, Turkey earthquakes. The modal analyses of the models have shown that the structural periods and the overall structural response are influenced by the minaret height and spectral characteristics of the input motion. The dynamic displacement and axial stress time histories are computed at the critical points on the minarets. During recent earthquakes, most minaret failures occurred above the base of the structure. Consistent with the observed response, the largest stresses were calculated at the same location.

Investigation of dynamic response of masonry minaret structures

Minarets are very slender structures with an old existence. The historical ones are made of cut-stone-block masonry assembled in peripheral cylindrical wall with an interior helicoidal stair supported on a central core and on the wall. They are spread throughout the Islamic world and constitute an important heritage not only of religious value, but also of great cultural interest. Throughout the times, these structures as part of a mosque, have suffered significant damage during the earthquakes. Istanbul presents interesting characteristics to evaluate their dynamic behavior, as they are in great number, in an area where a large event in the next 30 years has been predicted.

In this paper, we performed a series of in situ ambient vibration tests to old minarets of various sizes and compared results of frequencies with numerical modeling of the same structures. For the low-amplitude motion, the frequency values of the first modes can be obtained from an empirical formulae function of the inertia of the cross-section and of the height of the main ‘body.’ Damping ratios for these amplitudes are of the order of 0.5–1.0%.

Dynamic linear analyses of these structures indicate that for most cases very high stresses develop for PGA above 0.5 g, an input with a reasonable chance of occurring in the next 30 years. These high stresses are expected to cause the toppling of the minarets in the form that has been observed in the recent past events. Copyright © 2011 John Wiley & Sons, Ltd.

Minaret behavior under earthquake loading: The case of historical Istanbul

Experimental analysis of seismic resistance of timber-framed structures with stones and earth infill

https://openaccess.city.ac.uk/3562/1/CULHER%2DD%2D11%2D00012%2Daccepted.pdf

Detailed and simplified non-linear models for timber-framed masonry structures

Experimental frequencies and damping ratios for historical masonry arch bridges

http://ramazanlivaoglu.com/pdf/49622_son_article.pdf

Traditional wooden buildings and their damages during earthquakes in Turkey

Turkish historical arch bridges and their deteriorations and failures

Many historical and new masonry minarets were damaged or collapsed during the 1999 earthquakes in Kocaeli and Duzce, Turkey. These and other recent earthquakes not only caused loss of property but also loss of many lives. The structural failures and resulting casualties have led to discussion and investigation of potential reasons for poor seismic performance of masonry minarets. The primary goal of this study is to review the construction practices for historical and new masonry minarets in Turkey and to discuss the seismic damage observed in those structures. The architectural and structural properties of contemporary and historical Ottoman minarets and their components are presented. For example, a very old special technique for reinforcing and linking adjacent stone blocks with iron pieces in the vertical and horizontal directions is discussed. The structural damage examples are used to better understand the reasons for the observed failure mechanisms. It is concluded that the transition region betwee...

Ö. İskender Tuluk

Papers

Traditional wooden buildings and their damages during earthquakes in Turkey

Turkish historical arch bridges and their deteriorations and failures

Traditional Turkish Masonry Monumental Structures and their Earthquake Response