Vulnerability assessment for medieval civic towers

The seismic vulnerability of an ancient civic bell tower is studied. Rather than seeing it as an intermediate stage towards a risk analysis, the assessment of vulnerability is here pursued for optimising the retrofit design. Vulnerability curves are drawn by carrying out a single time history analysis of a model calibrated based on experimental data. From the results of this analysis, the medians of three selected performance parameters are estimated, and they are used to compute, for each of them, the probability of exceeding or attaining the three corresponding levels of light, moderate and severe damage. For future development, the same model can be used to numerically implement the effects of different retrofitting solutions and to re-estimate the associated vulnerability curves. The ultimate goal is to provide a numerical tool able to drive the optimisation process of a retrofit design by the comparison of the vulnerability estimates associated with the different retrofitting solutions.