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In this paper a hybrid approach for the seismic vulnerability assessment of the existing modern masonry buildings is developed. The procedure takes advantage of the standardized designs and technological features of the XX century masonry structures to define a hybrid framework constituted by two different phases: an urban scale one and one at the building level. The methodology is applied at the external outskirt of the city of Florence, where the residential stock is characterized by a significant number of masonry constructions. At the urban level a cognitive research based on archive research and data collection allowed the identification of the architectural and structural features of modern masonry buildings. Then, a selected case study representative of a wider class is chosen for a probabilistic procedure based on nonlinear static analysis and targeted at the derivation of fragility curves. The analytical results have been assumed to calibrate a simplified procedure available in literature and targeted at the definition of bilinear capacity curves. The calibration of the different coefficients was conducted in terms of generic outcomes, defining correlations within architectural elements and their seismic behavior (facades, side walls). The rapid methodology has been finally implemented at the urban scale, and the results of the work exhibit a relevant vulnerability of existing buildings. The simplified methodology overcomes the limits of the empirical methodologies at the urban scale constituting a valid tool for the rapid seismic vulnerability assessment at urban scales of the modern masonry structures of different contexts. [ABSTRACT FROM AUTHOR]

The heritage value of the mixed wood-masonry 18th century Pombalino buildings of downtown Lisbon is recognized both nationally and internationally. The present paper focuses on the seismic assessment of global response and retrofitting of a typical Pombalino building by nonlinear static analyses, performed by the research software Tremuri, which is able to model 3D configurations. The structure is modelled using nonlinear beams for masonry panels, while in case of the internal walls (frontal walls) an original formulation has been developed in order to take into account their specific seismic behaviour. Floors are modelled as orthotopic membrane finite elements: this feature allows to simulate the presence of both flexible and rigid diaphragms, being the first ones more representative of the original state while the second ones of retrofitted configurations. Seismic assessment has been evaluated by applying nonlinear static procedure and comparing the performance of different configurations (by considering various retrofitting strategies). Finally, assuming a lognormal cumulative distribution, fragility curves are obtained to be representative of Pombalino buildings: the most important application of such curves is for seismic risk and loss estimation analyses. [ABSTRACT FROM AUTHOR]