CSSI: A novel climatic-seismic severity index to assess the integrated energy-structural performance of existing RC buildings

Integrating seismic retrofitting with energy efficiency measures has been historically neglected in the design codes due to a lack of robust methodological frameworks. To this end, this study presents a pioneering integrated classification index, the Climatic-Seismic Severity Index (CSSI), which is used to evaluate the energy and structural/seismic performance of existing reinforced concrete buildings on a regional scale. We propose a novel stochastic framework to determine the economic impacts stemming from energy use and seismic damage in the existing building stock based on Representative Building Samples drawn from a substantial subset of the stock. As a regional case study, simulations are conducted by varying climatic and seismic conditions in the whole geographic area of Italy. Findings indicate a significant variation in the integrated economic performance, with expected expenditures ranging from 10 to 50 €/m2y, prompting the need for targeted policy development. This framework offers valuable insights for directing retrofitting strategies that concurrently prioritize energy efficiency and seismic resilience.