Vibration Mechanism of 13th Century Historical Menar-Jonban Monument in Iran

Abstract    Historical monument of Menar-Jonban (shaking tower) is located in the famous city of Isfahan in central Iran. Initial construction of this interesting and unique masonry monument belongs to 700 years ago. This monument has two vibrating circular towers of 7.5 m height. These towers are separated from each other by a distance of 9.2 m and constructed on top of an ancient tomb of 10 m height. When one of the towers is shaking by the human force, the other one immediately starts to vibrate without transmitting any significant vibration to the other parts of the structure. This unique dynamic behavior has become a puzzle to architects and structural engineers for many years. Visitors from all over the world, climbing to the top of one of the towers and by shaking one, cause automatic shaking of the other tower. In this paper, the description of the structure, free and forced vibration tests setup, test results and findings on this unique structure is presented. Moreover, to identify the dynamic characteristics and behavior of this monument, analytical studies have been performed and the results of the various possible mathematical models were compared with measured response for system identification purposes.