The impact of earthquakes on the life cycle carbon footprint of existing buildings

The transition toward a low carbon society is nowadays recognized as a worldwide priority. In the building sector, such a mission is typically associated to the refurbishment of existing buildings by reducing the operational energy consumption and by moving toward sustainable and renewable energy in the supply chain. These actions are accomplished, among others, by the upgrade of the thermal insulation and the use of thermal and photovoltaic solar energy. In earthquake prone regions, the refurbishment of existing buildings could be jeopardized by the damage associated to seismic events, especially if the considered buildings were not designed according to modern building standards. Therefore the application of solely energy-upgrade interventions on such buildings could lead to an unexpected and reduced environmental efficiency, besides representing a safety hazard. In the present paper, the PEER-PBEE framework is specifically derived to address the embodied carbon of existing buildings related to seismic events. The investigated procedure is suitable for evaluating the effectiveness and environmental impact of the refurbishment of existing buildings in seismic prone areas. The procedure is applied to a selected case study after thermal refurbishment with and without seismic retrofit. The results, also projected at district level, show how inherent seismic vulnerability and site seismicity affect the environmental impact evaluation of the considered buildings.