Influence of cost-optimal energy retrofit solutions on seismic economic losses of existing buildings

It is a fact that most European buildings built before 80ies were constructed without any design concern for energy efficiency and environmental sustainability. In addition to this issue, over the last decades, the essential need of safer buildings has progressively attracted the interest of scientific community and government institutions. However, the strong interaction between energy and structural aspects in the design of building retrofit has never been handled through robust and reliable approaches. The present study aims to explore this knowledge gap by introducing a methodological framework which enables to address the retrofit of existing buildings by integrating energy, structural and economic aspects. To this end, a multi-stage energy optimization is carried out by implementing a genetic algorithm and a smart research strategy. Thus, the cost-optimal energy retrofit solutions are identified and their influence on the expected economic losses due to seismic damage is assessed throughout the building lifetime. The retrofit assessment methodology is applied to a multi-storey residential building, considering the effects of two different building locations, namely Milan and Norcia. These latter are characterized by similar climatic conditions (Italian climatic zone E) but by a different level of seismic risk, higher for Norcia. The outcomes show that the estimated seismic economic loss associated with each optimal energy retrofit solution is strongly affected by the building location; thus, the selection of the optimal energy retrofit measures should be related to the structural behavior of a building in order to achieve reliable economic and sustainability benefits.