A life cycle framework for the identification of optimal building renovation strategies considering economic and environmental impacts

It is well-known that the existing building stock is responsible for non-renewable resource depletion, energy and material consumption, and greenhouse gas (GHG) emissions. Life cycle analysis (LCA) procedures have thus been developed, in recent years, to assess the environmental impact of construction and operational phases through the entire building life cycle. Furthermore, the economic, environmental, and social consequences of recent natural disasters have encouraged the additional integration of hazard-induced impacts into common LCA procedures for buildings. Buildings are however expected to provide the population with safe living and working conditions, even when hit by different types of hazards during their service life, such as earthquakes. Hence, next-generation LCA procedures should include not only hazard-induced impacts, but also the contribution of potential retrofitting strategies that may alter the structural and energy performances of buildings throughout their remaining service life. This study presents a life cycle framework that accounts for the contributions of initial construction, operational energy consumption, earthquake-induced damage repair activities, potential retrofitting interventions, and demolition (considering also its associated potential material recycling), in terms of both monetary costs and environmental impacts. The proposed methodology can be used to undertake cost-benefit analyses aimed at identifying building renovation strategies that lead to an optimal balance, considering both economic and environmental impacts, between reduction of seismic vulnerability and increase of energy efficiency of a building, depending on the climatic conditions and the seismic hazard at the site of interest.