Integrating seismic and energy retrofits in built heritage: timber-based solutions within the “nested building” approach

Ensuring the long-term preservation of the built heritage addresses two key aspects: the safeguard against natural hazards like earthquakes and the update of performances to contemporary standards. The paper discusses the use of the Nested Building retrofit technique, aiming to achieve an integrated refurbishment strategy for existing masonry buildings, by introducing a Cross-Laminated Timber endoskeleton designed to update structural, thermal, and functional performances. The study discusses the application of this technique to a heritage building, adopted as a pilot case. The capability of Nested Building in integrating seismic and thermal enhancement was assessed by employing global numerical simulations. Seismic strengthening was evaluated through non-linear static analyses in a finite element environment, whilst the energy savings were computed through a dynamic energy simulation tool. A range of layouts was explored, implementing incremental levels of strengthening and insulation. The study revealed the effectiveness of Nested Building technique in integrating the seismic and thermal retrofit of masonry buildings. Notably, even when applied to a specific portion of the building system, the intervention still provides valuable improvements.