Seismic Strengthening and Energy Efficiency: Towards an Integrated Approach for the Rehabilitation of Existing RC Buildings

TLDR

Most Italian residential buildings were built before 1981, when only 25 % of the territory was seismic‑rated, and thermal performance standards were introduced only in 1991, leaving the existing stock with large seismic and thermal deficits. The paper advocates integrated, sustainability‑oriented rehabilitation for the many buildings that lack adequate seismic and thermal performance. Using Incremental Dynamic Analyses on a representative RC building, the study compares seismic performance of two thermal retrofits—replacing masonry infill walls and adding double‑skin RC frames—to assess their impact on both seismic and thermal behavior.

Abstract

In Italy, most of the residential buildings (77%) were constructed before 1981, when only 25% of the national territory was classified as seismic. Further, the first provisions addressing thermal performance criteria were introduced in 1991, when about 88% of the existing Italian buildings had already been realized. Therefore, the Italian building stock is characterized by a large deficit in terms of both seismic capacity and thermal insulation. The large number of buildings having inadequate performance, both seismic and thermal, calls for rehabilitation interventions that are based on an integrated and sustainability-oriented approach. In the paper, the influence on seismic performance deriving from some retrofitting techniques, generally adopted to enhance the thermal performance of infill walls, has been evaluated. A common residential RC building representative of existing buildings designed only for vertical loads has been studied. The seismic performances have been evaluated through Incremental Dynamic Analyses (IDA). A first comparison is related to a thermal retrofitting intervention made by replacing the existing masonry infill walls with new elements that are able to ensure an adequate thermal protection. Further, a retrofitting intervention based on the “double skin” technique, where new infilled RC frames are added and connected to the existing ones, has been investigated in terms of seismic and thermal performance.