FRAGILITY CURVES OF MASONRY BUILDING AGGREGATES INCLUDING BAYESIAN MODEL UPDATING

Masonry building aggregates are often irregular and complex structures. Plan and elevation irregularities, uncertainties on the mechanical parameters of the masonry, and lack of information about the connections between structural units are all features making difficult to perform accurate seismic analyses. The difficulties in modeling the seismic behavior of such complex structures are further increased by the necessity to minimize the number of in situ tests because building aggregates are mainly historic structures. Vibration-based measurements on real buildings are non-destructive techniques that allow acquiring relevant information on their global dynamic behavior. A Bayesian model updating procedure is here proposed to update a finite element and an equivalent frame model of a masonry building aggregate starting from information provided by vibration-based tests on the real structure. The procedure improves the definition of the likelihood function since allows the decoupling of measuring errors and modeling uncertainties in its computation. The updated models have been later adopted to perform seismic analyses aimed at deriving fragility curves. The entire procedure has been applied to a real masonry building aggregate including the development of full-scale dynamic measurements.