A mechanical approach for estimating regional fragility curves of existing RC buildings stock in Puglia

The study of the seismic vulnerability of Reinforced Concrete (RC) buildings is a topic of large interest for the scientific community and public institutions, who have the task of providing mitigation strategies for the seismic risk for a wide and inhomogeneous portfolio of buildings with very limited economic resources. With this regard, within the research project ReLUIS 2014-2018, typological and structural information about recurrent classes of RC buildings was collected in some municipalities of Puglia, Italy. Based on these data, it has been possible to identify some representative “Index” buildings, characterized by common morphological, mechanical and geometrical features and identified by a set of relevant characteristic parameters having a defined variation within a plausible range. In this paper, based on the available dataset of building information in some municipalities and on the results of seismic vulnerability analyses about residential RC building typologies, the fragility of representative Index buildings has been investigated. In particular, by using the data collected from a previous large-scale investigation performed in the Municipality of Bovino, preliminary regional fragility curves have been derived for of the index buildings previously defined. The significant mechanical parameters have been varied within pre-defined ranges; for each obtained “sample” simulated design has been made deriving the computational model; at last, the assessment has been performed through the development of a pushover-based procedure. The variation of the parameters and their combination have been carried out in order to appraise their influence in the regional seismic fragility.