The Effects of Construction Techniques and Geometrical Properties on the Dynamic Behavior of Historic Timber Minarets in Sakarya, Turkey

Abstract

Sakarya City, as the host of many civilizations, has many historic monuments. The city is in the most active earthquake zone in the region. The minarets of mosques are the most important structures because they are slender. Therefore, they are sensitive to lateral loads, and earthquakes and strong winds may cause damage to these structures. The highest number of mosque minarets partly or totally collapsed in the 1999 Kocaeli and Düzce earthquakes that occurred in Turkey. The region is rich in trees, so timber has been used in the construction of different structures in Sakarya City and the vicinity for many years. In this study, five historic timber minarets in Sakarya City were experimentally and computationally examined to determine the effects of the construction techniques and geometrical properties on the dynamic behavior of the minarets. Ambient vibration tests of timber minarets were performed, and the construction techniques and geometrical features were examined; the results of these are discussed below. It was determined that the outer wall construction technique, body height, slenderness, and cross-sectional area play important roles in the dynamic behavior of timber minarets. Finally, an empirical formula was derived from the relationships for rapid estimation of the fundamental period of timber minarets.

Tari̇hi̇ Dört Ayakli̇ Mi̇nare’de Zemi̇ne Dayali Strüktürel Sorunlarin Yeralti Radari İle Beli̇rlenmesi̇

“…In many periods from the past to the present, minarets have been built in mosques for the purpose of reciting the azan and making reciting the azan heard. In this context, the first minaret example in the mosque was built in the Mosque of 'Amr ibn al-'As in Egypt in 673 AD, and it was built with a balcony to announce the azan [6]. Minarets, which were built from stones, bricks, and wood, did not have a certain shape in the beginning and there are two styles of minarets that might be described in general: the first style is inspired by ancient lighthouses and/or bell towers having a square/rectangular cross-section in-plane and the second style that originated in Asia constructed in a cylindrical slender body [7].…”

“…Minarets can be considered one of the distinctive and essential structural components of the Islamic cityscape [8]. Throughout history, countless majestic minarets have been built in various parts of the world adapting structural approaches and utilizing various materials [6]. Similar to many other ancient structures, the historical minarets are made of brick/stone and mortar and they are regarded as tower-like structures [9].…”