Review of methods for the combined assessment of seismic resilience and energy efficiency towards sustainable retrofitting of existing European buildings

Sustainable retrofitting of existing buildings is a prerequisite for achieving climatic and energy objectives in the EU. Thus, practical tools supporting the evaluation and decision-making process when planning retrofit interventions are required. In specific areas, in addition to energy efficiency, the improvement in building resilience to natural hazards is requested; in several European regions, seismicity poses a significant hazard. This study aims to analyse the state-of-the-art of the integrated methods for the implementation of structural and energy retrofitting. The work consists of reviewing available tools, international sustainability protocols, and methods specifically developed for combined energy and seismic assessment. In the first group of methods, assessment is independently referred to specific criteria for energy performance and seismic safety, quantified according to available codes. Besides, in a second group, integrated evaluation is achieved considering 'equivalent' initial or life-cycle costs associated with energy consumption and seismic vulnerability. The collected methods were evaluated for qualitative requirements for optimal integration, such as multidisciplinary, life-cycle approaches, and other indicators. Finally, a critical evaluation is provided, highlighting what can be used for future developments toward a sustainable and resilient retrofitting of existing European buildings.