The masonry buildings constructed between the 19th and 20th centuries in Lisbon are commonly recognized for their eclectic style and structural vulnerability. This article presents the main characteristics of these buildings in the aim of preserving their cultural value. The socio-economic conditions on what they were constructed are identified. This includes the possible reasons for the negative impression attributed to the buildings, which end up to be known as “gaioleiro” (meaning bird cage). The architectural features are described in terms of urban plan and aesthetics, configuration of the buildings and layout of the flats. The structural system and materials are characterized. In addition, an estimation of the mechanical properties of the materials is presented based on the Bayesian approach. The main weaknesses and alterations implemented are also identified, putting in evidence the possible consequences for the structure and seismic performance.

The seismic performance assessment of buildings is a challenging process

This article describes the application of the procedure for the derivation of fragility functions presented in the companion article entitled Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: methodology and application at building level. The procedure, based on the execution of non-linear analyses, was developed to be applied to unreinforced masonry buildings considering both the in-plane and out-of-plane response. Different sources of uncertainty, both epistemic and aleatory, affecting the behaviour of these unreinforced masonry buildings are discussed and treated with a probabilistic procedure. The fragility curves determined for the different classes of buildings are compared and then combined to define the final fragility curves for these unreinforced masonry buildings. The results put in evidence the high seismic vulnerability of these buildings and the urgent need for the structural intervention and for the design of retrofitting measures in order to reduce potential losses due to future earthquakes.