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Vulnerability assessment of masonry historical monuments relies on the accurate assessment of their real structural and foundation conditions, which is always a very difficult and challenging task to determine. Ambient noise measurements are among the non-destructive field techniques, which can provide useful information regarding the structural integrity, the dynamic response characteristics of the structure and the dynamic properties of the foundation soil. The performance-based design approach developed in the research project PERPETUATE for the vulnerability assessment of monuments uses all this information in a cost efficient way. Moreover, validation of the whole methodology has been made on several monuments in the Medieval City of Rhodes. To illustrate the use of ambient noise measurements in the frame of PERPETUATE methodology, we performed a number of ambient vibrations measurements on three selected monuments in the Medieval City of Rhodes (Greece) and the surrounding soil. The aim was to identify the dynamic characteristics of the selected structures and the dynamic properties of foundation-soil where these structures are founded. The Frequency Domain Decomposition technique is adopted for ambient modal identification using ARTeMIS software and the continuous wavelet transformation for calculating the wavelet energy to compare it with the pathology pattern of a typical masonry wall. The dynamic properties of the foundation soil, in terms of shear-wave velocity, were also explored using the Spatial Autocorrelation Coefficient method. The goal of the ambient noise measurement performed herein is to better simulate the complex masonry structures in view of estimating their vulnerability using the PERPETUATE methodology and support rehabilitation decisions. The improvement of the initial numerical model using the results of the ambient vibrations measurements illustrates the usefulness of the approach and provides some helpful practical guidelines. [ABSTRACT FROM AUTHOR]

The present study focuses on the dynamic system identification of the Suleiman Mosque minaret in the medieval city of Rhodes, Greece. Suleiman Mosque was built in 1522 at the site of the destroyed Christian Church of the Apostles. First, we performed sets of ambient vibration measurements at the minaret of the monument. Based on these data, we calculated the eigenproperties of the minaret. Next, we modeled the monument in three dimensions, using the finite element method. Six numerical models were considered. Model Ι is the simplest one (isolated, fixed base minaret). Model VI is the most complicated one (simulation of the whole mosque also considering soil–structure interaction and foundation flexibility). The calculated predominant periods and mode shapes of Models I–VI are validated against the microtremor field measurements, recorded on the minaret's two floors and ground level. We elaborate on the reliability of finite element models for earthquake response evaluation, considering soil–structure interaction and foundation flexibility on the mode shape eigenfrequencies. Additionally, we discuss the seismic response of the minaret compared to the whole monument. We observed no significant difference in the first two modes of response, implying that the minaret's dynamic behavior is slightly affected by the entire mosque's presence. [ABSTRACT FROM AUTHOR]