PSI - Issue 44

R. Siano et al. / Procedia Structural Integrity 44 (2023) 1038–1044 R. Siano, A. Fatnassi, F. V. De Maio, P. Basso, M. Cademartori / Structural Integrity Procedia 00 (2022) 000–000

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limit state, defined with reference to the PGA of structure capacity for each limit state, and the repair costs associated to the damages induced by seismic events occurred during the building life, measured as percentage of the cost of building replacement. Fig. 2 and Fig. 3 report a summary of the loss curves obtained for the groups of buildings described. It is possible to observe that the bigger benefit in terms of EAL is obtained for the buildings that belong to the group 3 with the bigger seismic vulnerability in the existing conditions, the buildings sample included in group 3 is also generally the sample characterized by the highest seismic vulnerability in the existing configuration. A remarkable benefit in terms of EAL is also obtained for the buildings included in group 2, for which the regularity of the geometrical form allowed an efficacy distribution of seismic loads and generally improves the structural performances. 6. The definition of a seismic vulnerability database The data provided by the case study were included in a larger database that collects all the data provided by seismic vulnerability studies performed in the last years by RINA consulting on existing buildings. The data, divided for structural typology of the buildings sample (RC, steel and masonry buildings), aimed at providing first of all a reference for further seismic vulnerability analyses, but also for predicting retrofit strategy and costs as a function of the seismic vulnerability index and mechanical characterization of the structural components in the pre-intervention configuration. Correlations between the structural efficiency of the retrofit strategies as well the retrofit costs and specific parameter identifying the initial structural configuration of the building, such as the mechanical properties of structural components and the initial seismic capacity, was investigated. The impact of the improvement of seismic requirements provided by the national codes during the last decades can be also analyzed with the aim to identify a criterion to give priority to public investments in the improvement of the seismic safety of public buildings as a function of the susceptibility of the specific structural systems and details to be improved. 7. Conclusions The study presents the applications of consolidated seismic assessment methodologies to a large sample of existing public buildings located in Italy. The project includes several buildings located in regions prone to very high seismic hazard and characterized by strategic uses. The analyses started from the definition of the initial structural configurations of the buildings by studying their design configurations and the eventual interventions suffered over the time, but also by performing the mechanical characterization of the structural materials and the geotechnical and seismic characterization of the site. Once defined the initial structural configuration of the buildings sample, all the structures were submitted to linear and nonlinear analysis to define their seismic vulnerability and identify their structural criticalities. The identifications of the structural deficiencies allowed the definition of specific retrofit scenarios aimed at guaranteeing the fulfillment of the seismic performance level provided by the current national code. At last, the development of cost-benefit analysis, based on the definition and comparison of loss curves, allowed the estimation of the efficiency of each retrofit scenario in terms of both structural performance and economic impact. The collected data form part of a larger database including the most common structural systems, moving from masonry structures to reinforced concrete and steel structures, built along a significant reference period span from the 40's to the 90's. This seismic database allowed the analysis of correlations between the structural and economic efficiency of retrofit scenarios and the specific parameters correlated to the initial structural configuration, such as the mechanical properties of structural components and the initial seismic capacity. The final goal of the study and the data collection is to provide a criterion for predicting retrofit strategy and costs as a function of the seismic vulnerability index, but also to identify a criterion to lead private or public investments with the aim of maximizing their efficiency accounting for the susceptibility of the specific structural systems and details to be improved.