A Procedure for the Structural Identifcation of Masonry Towers

Historic masonry towers, as well as bell towers, minarets and chimneys, represent an important part of the Mediterranean basin architectural heritage. Widely spread out on the Italian peninsula, the bell towers refect cultural, social and religious aspects of the communities, thus, their conservation remains an open challenge for scientists, governments and local communities. The seismic behavior of slender masonry structures is, generally, characterized by the combination, of the static vertical loads with dynamic loading. However, the determination of the structural behavior of masonry structures is always a complex challenge due to the material inhomogeneity, manufacturing imperfections, geometric confguration or structural interaction between the layers in the case multi-leaf masonry structures. In this research, an expeditious and low-cost procedure for the structural identifcation of historic masonry towers is proposed. The procedure, based on experimental measurements and numerical modeling, aims at the estimation of the average mechanical characteristics under service loads. In particular, the procedure proposes the acquisition of the fundamental frequency by means of a single compact digital tromograph and successive fnite element model calibration starting from the experimental data. The whole identifcation procedure has been at frst verifed on an elementary laboratory specimen, then applied on the historic bell tower of Basilica dei Frari located in the historic city center of Venice