Dynamic identification of moumental and historical minaret of the Sehadet

Abstract

Modal analysis has been used in three decades in the civil engineering disciplines in order to solve complex structural dynamic problems. In this study, dynamic parameter such as fundamental frequency, mode shapes and damping ratios of minaret of Sehadet mosque, historical masonry minaret, was investigated using operational modal analysis method. However; dynamic character identification of historical masonry minarets are considerably difficult for Structural Health Monitoring. The historical masonry minarets have complicated stiffness, heterogenic element material and direct indeterminable boundary conditions. Thus, scope of this study, ambient vibration test which is measure in-situ tests were carried out for determination of dynamic characteristics with the aid of accelerometers and appropriate analysis programs. In order to achieve the modal analysis-frequency domain, Peak-picking method was employed in derivation of modal data from frequency response function data. In addition ultrasound test was performed to the material taken from minaret elements, which is coarse (küfeki) stone and laboratory test was made to the stone sample for the characteristic properties of material. Thereby, only few criteria such as boundary conditions and mesh control calibration was made for the correct model of the minaret. Three dimensional finite element model was designed for the minaret using finite elements analysis program, ABAQUS. The results obtained from a finite element analyses of the minaret were compared with results of experimental approach. Finally, it can be easily stated that the proposed finite element models themselves are the meritorious approximations to the real problem, and this makes the model appealing for use in comprehensive investigations.