Earthquakes and Structures, Vol. 7, No. 1 (2014) 57-82 DOI: http://dx.doi.Org/10.12989/eas.2014.7.1.057 57 Seismic assessment and retrofitting of Pombalino buildings by pushover analyses Helena Meireles13, Rita Bento1b, Serena Cattari*2 and Sergio Lagomarsino2c 1ICIST, Institute Superior Tecnico, University of Lisbon, Av. Rovisco Pais 1049-001, Lisbon, Portugal 2DICCA, Department of Civil, Chemical and Environmental Engineering, University of Genoa, Via Montallegro 1 - 16145 - Genoa, Italy (Received June 27, 2013, Revised March 1, 2014, Accepted March 3, 2014) Abstract. 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 orthotropic 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. Keywords: pombalino buildings; equivalent frame model; retrofitting; nonlinear static analysis; fragility curves 1. Introduction The heritage value of the mixed wood-masonry 18th century Pombalino buildings in downtown Lisbon is recognized both nationally and internationally. In 1755 a catastrophic earthquake followed by a major tsunami struck the capital of Portugal causing severe damage to the city. The Prime Minister at the time, Marquis of Pombal, was set in charge of rebuilding the city and he delegated to a group of engineers the development of a structural solution that would guarantee the required seismic resistance of the buildings. Based on the know-how of that time and on the empirical knowledge gathered from the buildings that survived the earthquake, a new type of ♦Corresponding author, Assistant Professor, E-mail: serena.cattari@unige.it aE-mail: helenaalvesmeireles@gmail.com bE-mail: rita.bento@tecnico.ulisboa.pt cE-mail: sergio.lagomarsino@unige.it Copyright © 2014 Techno-Press, Ltd. http://www.techno-press.org/?journal=eas&subpage=7 ISSN: 2092-7614 (Print), 2092-7622 (Online)