Dynamic investigations on medieval masonry towers: seismic resistance and strengthening techniques

Most part of Mediterranean area has been classified seismic. If for the new buildings a suitable code can be adopted and the material and the technology can give an effective contribution to the seismic resistance of the structure, for the old masonry monument only a reliable structural analysis and some specific and not much invasive retrofitting can be adopted. In this context, the towers are a very interesting case study because more vulnerable to the horizontal actions, but also because more emblematic to study some peculiar behavior of the material. In the paper the seismic behavior of two Middle Age’s towers has been presented and analyzed. One of the most important aspects studied is the seismic vulnerability, considering also the specific non linear behavior of the material with a limited tensile resistance. Seismic assessment was carried out with non linear static analysis under a multimodal distribution of the lateral loads. Some remarks on innovative reinforcing technologies adopted to improve seismic resistance of the towers will be presented and discussed.