Seismic Analysis and Retrofitting by C-FRP of Reinforced Concrete Bell Towers Within Masonry Churches: A Case Study

Bell towers are slender structures of variable dimensions that are highly subjected to seismic damage due to their structural characteristics. The seismic response of bell towers and the design of potential retrofit interventions depend on their configuration, either isolated or connected to other constructions making part of ecclesiastic complexes. The different seismic behavior of bell towers depending or less from the interaction with other structures is evaluated in the current work, which analyses a case study of a RC tower inserted within a masonry church placed in the municipality of Torre del Greco, in the district of Naples (Italy). Three different macro-element models of the RC bell tower developed with the 3MURI software are considered: the tower alone, the tower together with the masonry structure just below its vertical projection and the tower including the whole volume of the church. Whereas the isolated model overestimates the bell tower seismic capacity, modelling of other structural part allows to obtain more reliable prediction of the real behavior of the tower. Based on the achieved seismic response, a suitable retrofit intervention with C-FRP fibers is planned for seismic upgrading of the tower through improvement of the performance of beams and columns under bending moment, shear and axial loads. The effectiveness of retrofit interventions is performed both locally, by performing the verification of structural sections, and globally, by analyzing the seismic behavior of the entire ecclesiastic complex.