One of the main challenges of our time is to make our cities more sustainable, promoting specific actions for the mitigation of and adaptation to climate change. However, to be considered sustainable, cities must also be safe to live in, particularly against natural hazards like earthquakes. But sustainability is still not always a priority in some European cities.
Luckily, in recent years, the EU has started putting in much more substantial ﬁnancial efforts to increase the sustainability levels of our cities: in the 2014–2020 budget over 5% of the European Regional Development Fund was allocated to sustainable urban development. These resources have mainly been driven towards energy efﬁciency and low-carbon measures, to reduce the energy bills and the hazard risks related to climate change (e.g., hurricanes, ﬂoods, storms, landslides, desertiﬁcation, melting of glaciers and sea level rise) that may cause signiﬁcant damages and fatalities.
Special attention is paid to existing buildings, which are responsible for about 40% of the ﬁnal energy demand and therefore represent a great opportunity for energy saving and decarbonisation. In particular, with the European Green Deal, renovation activities have been privileged over new constructions to limit urban sprawl and preserve the remaining natural environment. The deal emphasises the need for Member States to engage in a ‘renovation wave’ of public and private buildings.
However, less effort has been made to reduce the seismic vulnerability of existing real estate. And that is a lot of real estate: just in Italy around 50% of the residential stock is earthquake-prone, while over 80% of the same stock is highly energy-consuming and carbon dioxide-emitting. Due to a lack of or obsolete energy performance guidelines and seismic design codes at the time of their construction as well as ageing and degradation of the building materials, the energy performance of older buildings is inadequate. At the same time, their structural reliability is often also poor, meaning the buildings are not always safe. Consequently, the sustainability level of towns located in seismic areas remains inadequate, since most buildings and infrastructures are unsafe, i.e., not sufﬁciently earthquake-resistant.
Decarbonisation and seismic renovation are still largely treated as two separate issues. But in the context of the Renovation Wave strategy, it is important to consider seismic safety in earthquake-prone cities and towns: indeed, investing just into improving energy efficiency can turn out to be a waste of resources if one earthquake then destroys the renovated buildings.
For this reason, in earthquake-prone areas energy renovation must be combined with seismic retroﬁtting. This can prevent loss of life and damages caused by earthquakes, and avoid costs that would otherwise be duplicated, for instance those for building-site setup and scaffolds, as well as for cladding, plasters and other ﬁnishing. In the case of energy refurbishment only, the risk of a building located in seismic regions can be equalised to an additional annual embodied equivalent CO2 that almost equals its annual operational CO2.
Until recently, the renovation of existing buildings focused either on solving structural safety problems or on increasing the energy performance. The Energy Performance of Buildings Directive (EPBD) was set up as a framework for energy performance strategies, and, according to Pohoryles et al. (2020), it clearly indicates that besides reducing greenhouse gas emissions, fire safety and seismic risks (which affect the lifetime of buildings) should be addressed when planning long-term renovation strategies of buildings. As mentioned above, disregarding seismic risk and seismic retrofitting may cause misleading expectations on actual savings for an energy retrofitted building, as energy retrofitting alone does not lead to a reduction in seismic vulnerability and the energy retrofit may be lost due to an earthquake.
Nevertheless, many barriers significantly limit the real possibility of undertaking combined retrofit measures, especially in the case of multi-owner housing and high-rise buildings, says Giuseppe Margani, e-SAFE’s project coordinator. These barriers are of different kinds: economic/financial (high renovation costs, insufficient incentives and subsidies, landlord-tenant dilemmas, etc.), technical (ineffectiveness of conventional upgrade solutions, need of regulatory simplification, etc.), organisational (occupants’ dislocation and disruption, consensus to the retrofit expenditure by condominium ownerships, excessive time for getting construction permits, etc.), and cultural/social (insufficient information and skills, lack of adequate policy measures for promoting renovation actions).
In recent years, researchers have begun studying and analysing the topic of combined seismic and energy retrofitting, assessing the benefits of increasing seismic and energy performance of existing buildings through a single intervention. The study by Pohoryles et al. showed that in zones in which seismic retrofitting is essential due to higher seismic activity, performing the combined retrofit at once instead of separate interventions resulted in significant reductions in the payback period.
And this is exactly what e-SAFE aims to do. The project seeks to contribute to the deep renovation of EU non-historic building stock by developing an innovative, market-ready system that combines decarbonisation goals with earthquake resilience, indoor comfort, reduced implementation time and costs, affordable financing, reduced occupants’ disturbance, increased aesthetic and functional attractiveness. From a technological point of view, e-SAFE introduces prefabricated and customisable energy renovation panels, which are made up of a timber structure combined with wood-based insulating bio-materials (wood fibre, hemp, cork, cellulose fibre, etc.) and integrate high-performing windows and the desired finishing. These panels can be coupled with a structural system that increases the seismic performance, consisting of cross laminated timber (CLT) prefabricated panels connected to the existing reinforced concrete (RC) frame through innovative devices for seismic energy dissipation (dampers).
In those regions with the highest seismic risk, the existing RC-framed structure will be strengthened with a metallic exoskeleton, made of bi-dimensional bracings equipped with dampers and connected to the existing RC frame. All solutions are fully based on prefabricated components and dry technologies and can be implemented by operating from the outside of the buildings.
To further promote both seismic renovation and decarbonisation in earthquake prone areas we also need the right financial tools in addition to the technological ones. The financial tools and schemes help enhance market uptake as they will cater for a variety of customer types, be it families, public institutions, energy companies, corporate entities, etc. For this reason, the e-SAFE business model is structured strategically as a “one-stop-shop” so that the renovation process is as smooth, flexible, efficient and affordable as possible for all involved parties. After all, deep renovation should be a pleasant, people-orientated experience and a celebration of a new beginning, rather than a hassle and a confusing obstruction to normal life.
After all, according to the UN, every dollar spent reducing people’s vulnerability to disasters may save around seven dollars in economic losses.