Application of OMA technique to masonry slender towers: FEM updating and sensitivity analysis

Abstract. Bell towers are masonry slender structures prone to damage caused by vibrations due human activities, such as motor-vehicle traffic and operating machines in building sites, bells’ ringing and, of course, vulnerable strong induced earthquakes. Several studies with Operational Modal Analysis applications historical demonstrate that their modal properties typical recurrent depend mainly on the geometric features determining mass distribution boundary conditions adjacent buildings subjacent foundation soil. In paper a sensitivity analysis frequency obtained FEM eigenvalue soil modelling approach is carried out. The case study bell tower San Giuseppe Aci Castello church. natural frequencies tower, identified through OMA procedure considered for comparison.