Seismic fragility curves of masonry building aggregates including vibration-based Bayesian model updating

Masonry building aggregates are very complex structures to be analyzed under seismic actions. Plan and elevation irregularities, uncertainties in the connections between structural units added to those on the mechanical parameters of the masonry, are all features making difficult to perform accurate seismic analyses. The complexity is 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 to acquire relevant information on their global dynamic behavior. A Bayesian model updating procedure is here proposed to calibrate the elastic modulus of a masonry building aggregate starting from information provided by such full-scale tests. The procedure increases awareness in the definition of the likelihood function, since allows decoupling measuring errors and modeling uncertainties in its computation. The entire procedure has been applied to a real masonry building aggregate including the development of full-scale dynamic measurements.