A large portion of aging existing buildings are susceptible to significant structural damage during earthquakes and suffer from poor energy performance. When considering how to improve the seismic performance and energy efficiency of these structures, retrofitting has been shown to be a more attractive alternative compared to complete demolition and reconstruction. Not only is retrofitting generally preferable from an economic perspective, but it also typically has lower levels of social and environmental impact as well. Together, these three aspects (economic, social, and environmental) form the so-called three pillars of sustainability. Recently, research efforts have begun to focus on developments in combined and integrated seismic and energy retrofit frameworks and techniques, showing that investing in combined retrofitting schemes is often more cost effective than conducting either energy-efficiency or seismic retrofitting alone. As new national and transnational policies place greater emphasis on the environmental impact of the built environment, it is crucial that combined retrofit schemes be evaluated in a comprehensive manner that allows for the selection of optimal schemes when a range of key sustainability-related decision variables (DVs) are considered. This study investigated the selection of a life cycle assessment (LCA)-based optimal combination of seismic and energy-efficiency retrofit schemes for an existing reinforced concrete case-study building in Italy. The seismic performance of the retrofit schemes was evaluated using detailed nonlinear time-history analysis and the Pacific Earthquake Engineering Research Centre’s performance-based earthquake engineering (PEER-PBEE) framework, and the resulting economic costs and environmental impacts were incorporated into the LCA methodology. A detailed energy assessment was performed for each retrofit scheme so that the costs and environmental impacts associated with the operation of the building could be included in the LCA. Subsequently, the characteristics of each retrofit scheme were evaluated for a range of additional DVs, which encompassed the three pillars of sustainability. Finally, a multicriteria decision-making process was used to evaluate the optimal combination of seismic and energy retrofit schemes for several locations exhibiting different combinations of seismicity and climatic conditions. The results of this study provide insight into which combinations of seismic and energy efficiency retrofit measures can produce optimal solutions within the constraints set by decision makers and illustrate how assessments of both seismic and energy retrofit interventions can be implemented in the future.

The improvement of the seismic performance of existing buildings is majorly accomplished by adopting one or more retrofitting interventions. The selection of the latter is generally made considering conventional parameters, based on e.g. economic or structural considerations, without carrying out a comprehensive and integrated comparison of different retrofitting solutions. Instead, for an optimal choice of a retrofitting option, it is necessary to include different evaluation criteria to better assess the effectiveness of each strategy. This aspect becomes even more relevant when referring to buildings of strategic importance, such as school buildings, for which typical structural response-oriented criteria may not be enough to identify the best choice. This paper implements and scrutinizes various multi-criteria evaluation methodologies to comparatively assess retrofitting options for an existing reinforced concrete (RC) school building, considering different aspects, weighted according to their deemed importance. These evaluation criteria focus not only on the structural performance but also on how each intervention affects the operability of the building and on economic aspects. A comparative performance assessment is conducted on a detailed numerical model, able to reproduce the main structural deficiencies observed during past earthquakes in RC school buildings. Then, different retrofitting interventions are identified with the aim to solve the structural issues and improve the overall performance of the case-study school building. The seismic performance is quantified in terms of seismic losses, including the contribution of non-structural elements, amongst several other metrics. Finally, the outcomes of the different evaluation methodologies, which denote a non-unanimous optimal solution, are compared and critically analyzed.

Modern society requires that structures exhibit greater levels of resilience, especially under earthquakes. The seismic resilience of buildings is thus gaining increased attention as a particular, beyond-code approach. Seismically retrofitted buildings behave satisfactorily under expected earthquake scenarios; however, this does not guarantee operativity after a seismic event. This study critically reviews several methods currently available in the literature that quantify the seismic resilience level of buildings from different perspectives. An existing reinforced concrete school building, retrofitted according to four distinct strategies, is first evaluated in terms of seismic resilience levels. The overview and critical analysis of available resilience assessment frameworks determine the most suitable parameters to measure the seismic resilience for buildings. Subsequently, this metric is incorporated as an additional decision variable into an integrated seismic and energy retrofitting set of strategies. A multicriteria decision-making analysis is performed to select the optimally combined seismic and energy retrofitting alternative under social, technical, environmental evaluation, and seismic resilience aspects. We show how resilience impacts the preference for integrated seismic and energy retrofitting strategies, especially when this metric is considered as an annualized expected value.