Determination of Modal Parameters of Historical Masonry Minarets by Using Operational Modal Analysis

Abstract

This study conducted to investigation of modal parameters (such as mode shapes, modal frequencies) of a masonry type historical minaret by performing numerical and experimental analyses. Operational Modal Analysis (OMA) Technique is used for experimental study to obtain modal parameters of historical masonry minarets. For this purpose, Bu¨yu¨k Mosque located in Samsun, Turkey, was chosen for the experimental analysis. The Frequency Domain Decomposition (FDD) method is utilized to identify the natural frequencies and mode shapes experimentally. ANSYS software is used to carry out 3D finite element modelling of the historical masonry minaret and determine the natural frequencies and mode shapes of the minaret analytically. Furthermore, the finite element model of the minaret is calibrated according to the experimental results by using the Response Surface based finite element (FE) model calibration technique to obtain more accurate results of the modal parameters of the structure. The results of experimental, initial and calibrated finite element model were compared to each other. It can be noticed significant differences when comparing the results of the experimental and analytical with the initial conditions. Model calibration techniques are necessary to obtain more reasonable finite element model. © Avestia Publishing, 2016.