Enhancing urban resilience in historical centers: a scenario-based approach to seismic risk and strengthening interventions

The proposed study deals with seismic vulnerability assessment and highlights the importance of evaluating urban vulnerability in historic areas. Focusing on Portugal’s mainland, the case study area is located within the historical part of the Lisbon city council. The main objective of the proposed research is to evaluate the seismic vulnerability of existing unreinforced masonry residential buildings, given their prevalent nature and sensitivity to earthquake damage. This study, by providing an example of an urban-scale assessment approach, offers an overview of potential strengthening solutions and proactive risk-reduction measures in seismically-prone areas. To gather comprehensive information on the problem, a methodology was developed including site inspections integrated with remote sensing data. This combined approach highlighted the importance of conducting remote sensing with careful consideration and input from experts in building characteristics. Urban renovation works in historical centers often preserve architectural styles while altering physical structures. Without proper documentation, this revitalization can introduce errors, weakening the accuracy of seismic assessments. Expected damage scenarios were preliminarily estimated, and typological fragility curves were evaluated. Additionally, economic losses and repair costs were assessed. However, further studies are necessary to calibrate these results, particularly in terms of customizing the building typology characterization to the specific context of the Lisbon City Council.