From code to performance: Probabilistic seismic response of retrofitted precast RC buildings

Inadequate detailing in precast buildings designed under previous codes has proven to be a key factor in the seismic vulnerability of Italy's industrial heritage. Advances in structural assessment and refined hazard mapping have led to strategies now embedded in design guidelines, yet retrofitting existing buildings to ensure efficiency remains an open issue. This paper investigates the probabilistic seismic vulnerability of four single-story precast RC buildings constructed between the 1960s and 1990s in a high seismic hazard area according to the codes of the time. For each case, retrofit measures were designed following current standards and tailored solutions were proposed. Their effectiveness was assessed through advanced analyses at two performance levels, usability preventing damage and global collapse, using a probabilistic methodology that includes modal analysis, non-linear pushover, multi-stripe dynamic analysis, fragility curve derivation, and failure rate assessment.