Modal and Structural Identification of Historic Bell Tower in Čuntić, Croatia Using Ambient Vibration Testing

Abstract

In this study, modal and structural identification of a historic masonry bell tower in Čuntići, Croatia, damaged during the recent Petrinja earthquake, was performed. The results of the ambient vibration tests (AVT) and operational modal analysis (OMA) were used to update the finite element numerical model of the bell tower. Three modes were experimentally determined: the first two were bending modes (f1 = 4.395 Hz and f2 = 4.639 Hz), and the third was a torsional mode (f3 = 10.303 Hz). The experimentally determined and the originally calculated (preliminary NM) modal shapes agreed well, but in terms of modal frequencies, the correlation was poor. After model updating, some structural parameters were identified, and a reliable finite element numerical model was established. The proposed method can provide a reliable evaluation of the structural parameters of historic masonry buildings.

Exploration and Characterization of Dynamic Properties for Cultural Heritage Conservation: A Case Study for Historical Stone Masonry Buildings in Zanzibar

“…The operational modal analysis (OMA) becomes critical for the degrading historical structure to explore the dynamic characteristics, including the natural frequencies, damping ratio, and mode shapes, without the application of external forces. In this context, the identification of natural frequencies of the structure corresponds to the rate of alternation in stiffness, reflecting the vibrational properties, resonance, and motion characteristics at the intricate level of the structure [9][10][11][12][13][14][15]. For implementing new strategies, ambient vibration testing (AVT), a non-intrusive method that employs a non-destructive approach, relying on natural excitation sources, induces dynamic responses in the structure.…”