-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 analys es. Operational Modal Analysis (OMA) Technique is used for experimental study to obtain modal parameters of historical masonry minarets. For this purpose, Büyük 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 t he 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.

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SummaryThis study aimed to use the response surface (RS) method for finite element (FE) model updating, using operational modal analysis (OMA). The RS method was utilized to achieve better agreement between the numerical and field‐measured structure response. The OMA technique for the field study was utilized to obtain modal parameters of the selected historic masonry minaret. The natural frequencies and mode shapes were experimentally determined by the enhanced frequency domain decomposition (EFDD) method. The optimum results between the experimental and numerical analyses were found by using the optimization method. The central composite design was used to construct the design of experiments, and the genetic aggregation approach was performed to generate the RS models. After obtaining the RS models, an attempt was made to converge the natural frequency values corresponding to the five‐mode shapes with the frequency values identified by the experimental analysis. ANSYS software was used to perform 3D finite element (FE) modeling of the historic masonry minaret and to numerically identify the natural frequencies and mode shapes of the minaret. The results of the experimental, initial, and updated FE model were compared with each other. Significant differences can be seen when comparing the experimental and analytical results with the initial conditions.

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Experimental investigations of large and complex structural systems can be carried out by reduced-scale models in terms of convenience, time-saving and economical. This can be applied to different fields of study such as vibration, impact and explosion problems in structural engineering and allows reliable analysis to understand the static and dynamic behavior of real structures called a prototype. This study aims that a 1/3 reduced-scale model is created in the laboratory environment considering similitude requirements by selecting a single span historical masonry arch bridge as a prototype structure. For this purpose, the Operational Modal Analysis (OMA) Technique is utilized for experimental study to determine modal parameters of the prototype and model bridges. The similarity of the dynamic behavior of the reduced-scale bridge model and prototype are investigated. The analysis of the similarity in the dynamic behavior of the prototype and model bridge consists of comparing the natural frequencies and mode shapes by utilizing the modal assurance criterion (MAC) corresponding to the translational, bending and torsional modes. As a result of the study, it is concluded that the dynamic behavior of the reduced-scale bridge model is similar to the dynamic behavior of the prototype bridge.